1-bbl per two cyl carb (TriOffy i6 & Twin Edelbrock i4's)

Just notices the old Pony Ram carb system for the 2000 cc Pintos.

It boosted a 100 hp 121.5 cubic inch car to 110 hp, dropping the quarter mile half a second, and not hurting the fuel consumption.



http://www.cookieboystoys.com/vintage%2 ... lbrock.htm

It was a replacment of the 230 cfm at 1.5"Hg 5200 carb with twin horizontal split line float bowel 1940 List 1-6467 185 cfm 3.0 "Hg (265 cfm total at 1.5" hg). They are Holley/Autolite.Motorcraft branded 1940's with a few modifications. It pre-dated the 1978 model year Holley 1946. They are 1940 carbs, same as others made for some industrial 200 applications.There are 26 listings for 1940 carbs before 1974, then a stack more before 1978. 6467 and 7937 were just the tip of the ice berg for the old part numbers which were:-


small venturi 185 cfm on the little 144/170/200 stand in item if its PN coded as one of the following:-

R 4529 AAS, additional BPN plate suffix K
R 4530 AAS, additional BPN plate suffix L
R 4531 AAS, additional BPN plate suffix M
R 4532 AAS, additional BPN plate suffix N
R 4533 AAS, additional BPN plate suffix R
R 4535 AAS, additional BPN plate suffix T
R 4693 AAA
R 4694 AAA
R 4695 AAA
R 4697 AAA
R 4701 AAA and

and large venturi 200 cfm variants as replacements for the big 223/262/240/250 or 300 carb if its PN coded:

R 4454-AAS
R 4468 AAS
R 4509 AAS
R 4520 AAS, additional BPN plate suffix A
R 4522 AAS, additional BPN plate suffix C
R 4523 AAS, additional BPN plate suffix D
R 4524 AAS, additional BPN plate suffix E
R 4525 AAS, additional BPN plate suffix F
R 4526 AAS, additional BPN plate suffix G
R 4527 AAS, additional BPN plate suffix H
R 4528 AAS, additional BPN plate suffix J
R 4536 AAS, additional BPN plate suffix Y (an early 223 replacement)
R 4537 AAS, additional BPN plate suffix Z (an early 262 replacement)
R 4692 AAA
R 4696 AAA


Thanks to user rjseibenick for measuring the venturi diameters and CZLN6 for starting the investigation process for these Auotolite 1100/1101 and Holley 1904/1908/1909 replacement and originally non Factory Ford Holley 1-bbl carbs



The Holley 185cfm or 212 cfm 1940, Mopar 202 cfm 1945, Ford's totlaay strange backwards facing float bowel 195 or 200 cfm 1946, Tempo/Topaz backwards facing float bowel1949 and 6149/6153 are all related 1-bbl carbs which orginated from Colt Industries Holley, but due to a massive patent and anti trust legilastion spat between the Federal Government, Ford and Bendix Stromberg Corp, the design got passed on to Autolite, then Motocraft, then back to Holley, then, finally Carter corp in 1983, but its not a Carter carb as such.

Here is a similar 7937 series 1940 carb close up:-








The Chrysler Corp 1945 and FoMoCo 1946 are different, but directly related to the 1940.




Just reading viewtopic.php?f=2&t=66234&p=507444#p507444

FalconSedanDelivery":1nozbr12 said:

Ive Posted this before ( carb Orientation ) and it usually gets ignored , here goes ,( this applies to 2 brls and 4 brls Its a matter of part throttle flow , at wide open it dosen't matter , BUT , you don't drive that way, unless its a Race only combo , the throttle plates are situated in a way that they direct the fuel air mixture towards the rear , and as the secondarys open they direct to the front , on a V-8 Manifold that orientation works great , on an Inline ( that is STREET DRIVIN ) it will favor the rear cylinders and lean the front , if its mounted with the primarys facing the valve cover it will end up with a much better balanced mixture , NOW , you might say , my 1 brl was not that way , and that's true , but when all 6 cylinders pull from one source the directional effect is minimized , I realize you may think it should be would be tough to make up linkage , All you need is a bellcrank that pivots off the rear two bolts on the carb ( 2 or 4brl ) a example would be the original linkage on a Dual Quad 427 Ford , lots of examples / pics on line , in the end its your combo and money , just trying to help .

Click to expand...

Doesn't the carb orientation of these tip the rich part throttle air/ fuel ratio flow forward to number 1 and 3 cylinders, and then, under wide open throttle, doesn't it even out?

Thoughts, anyone?


FSD always said the carb position and nature of the Offy adaptor makes the triple Holley set up a little unpredicable in drag racing, most likely for the reasons stated above. Would making a 'knock off" six cylinder version in the same long runner, small diameter port intake (a triple Edlebrock 3 1-bbl carb Pony Ram for an I6!), be any better?

Thanks for an interesting post-Life was getting dull the last couple of days
I think the major boost came from straight individual runners from plenums that keep the distribution equal. IT"S THE RAM SAM!!
That intake valve doesn't close right at BDC and that intake column in the individual runner has momentum keeping the cyl filling. The 6th cycle getting into D. Vizard lingo!!
It was the design more than the CFM. Now add a little cam duration AND more CFM--Would be interesting.

my way":242z5vs6 said:

Thanks for an interesting post-Life was getting dull the last couple of days .......

Click to expand...

Its never boring researching the maliase and Clean Air act era Frauds, lots of really wack stuff was going on...you guys had ex NASA rocket scientists designing the 1978 EECII and 1979 EECIII on board engine control, 1978 fuel remaining computer, Trip Minder, Truck and LTD ABS systems, variable ratio pwer steering, and they even made a lame duck Fairmont chassis handle by putting French tires, slapper bars, limited slip diffs and strange horizontal shocks or Gattor back tires on 'em,

Reverse float bowl carbs, variable venturi carbs with onboard computers, Duraspark III ignition systems that got fired by a crank trigger and ECM in addition to the multiple spark box... Ford was way ahead of everyone else. All the tech got hidden in the screaming baroque land yachts with simulated sail cloth and bland four eyed box top compacts.

The real treasure was the overdrive gearboxes on everything from SUVs down to Pintos, Holley 2300CG and 4180c carbs on the Carpenter F 700 trucks with the 370 big blocks. And the steel cranked HD 300's, the 1940 carbed 200 Industrial engines, and the David Vizard style part throttle lean devices as altitude compensators, and bleed back carburation systems on the 4-bbl 4180c 5.0/5.8/6.1/7.5's...and feedback EECIV Holley 1949's and YF Carters.

And that all has kept every Ford chat room off the hookin for the last 20 years since someone invented them.

Off course, back in those days, when someone saw the Edison light bulb and Ford associated to gether, Mad Magzine lampooned it..http://d1g4sq00ps2bp3.cloudfront.net/images/9253mad.jpg.

Ford has a better idea :idea:


Buy a Datsun

my way":1m2q5i16 said:

......
I think the major boost came from straight individual runners from plenums that keep the distribution equal. IT"S THE RAM SAM!!
That intake valve doesn't close right at BDC and that intake column in the individual runner has momentum keeping the cyl filling. The 6th cycle getting into D. Vizard lingo!!
It was the design more than the CFM. Now add a little cam duration AND more CFM--Would be interesting.

Click to expand...

.


Well, the European 2.0 was tested with the 280 cfm at 1.5" 3.0 liter Essex V6 38 Weber DGAS, and it went up from 98 to 110 hp, but so did fuel consumption. The factory 1975-1980 RS2000 ran an improved exhaust, and got 110 hp. A Group One Spec engine with larger valves, twin Solex Downdraft carbs and the stock cam gave 145bhp.

The twin 1940 carbs were like a DGAS with approx 29 mm venturis. A set of 212 cfm at 3" hg carbs would be 300 cfm at 1.5" Hg, so the potential performance spike could have been 13%, or 125 hp with the bigger 1940 carbs 1.3" 33mm venturi.

:idea: Any ideas where the fuel mix would go to preferentially under cruise and wide open throttle. The throttle on the 1940 tips towards the radiatorl on that Pinto engine...can't imagine that would be good for even air fuel ratios.

With the plenum scarcely larger than the carb dia feeding only two runners and no log to run up and down, gotta think distribution
was pretty much a straight shot even with throttle blade deflection-probably more like mixing turbulence.
As far as fuel consumption claims They have to be made under the same driving conditions and demands. If you use the extra power it should use extra fuel to make it. If you cruse 60 mph with both set ups That would be comparable.
Would like to know the runner cross section dimensions they used on the 500cc cyl. Could start to get some ideas for the 550CC cyl of the 200. The right port velocity expanding into a larger valve pocket would get Bernoulli helping to gain pressure at the valve 8)
Should be getting some sleep here darn it :roll:
My way

I have the port dimensions on the Pinto, and they are too big for good economy, always were.They always created low velocity and poor economy and por low speed torque with this engine. The manifold was to redress the German designers penchant for autobahn head flow, something every Cologne I4, V4, or V6 has always had to contend with, from the Saab 96 V4 to the last 4.0 Mustang V6, mid range torque is high uo the rev range, and the rev range was higher than other domestics. The EAO/Pinto I4 ports were about 1-1/8" or 29 mm at the gasket face, great for power at 5200 rpm, and a 6600 rpm rev limit on some of the higher compression versions with headers as used in the RS2000. In a little 2040 pound Escort, the 110 hp version with 9.2:1 compression did 33 us mpg, 114 mph, 16 second quarters, but in an emissionised C3 automatic low compression 2450 pound Cortina with 90 hp, it wouldn't break 19 seconds or better 22 US mpg highway. David Vizard got a 68% performance boost out of his Cortina and automatic Pintos, with no fuel consumption increase, just by putting a proper Sig Earson cam, bigger vlaves, and apple porting the head to remove stagnant flow. He used a Lynx Dellorto intake, but found other log head Lynx manifolds were worse than the stock ones.

Low end torque was at 3500 rpm on the high compression engines, but it dropped sharply below that, and automatic C3/C4 versions langished because of large lift and duration figures off the seat. It was always badly matched untill the 1985 advent of port EFI for the European engines in the Sierra and Scorpio. Then it made 114 hp, and extra fuel economy and smoothness that the rattly 2-bbl never gave. No extra work was put into the engine after the 1979 duraspark and emissions work, it got a major fuel economy boost in that year, and higher gearing and that only acentuated the lack of low end torque.

I really am convinced you are right on the money with the signal to the carb...runners like that would bias the flow to each cylinder without much overshotting I'd say.

Ben diverted here, but this port thing is on my mind. That 1.125 port is small from my comparisons to other engines. For instance the early 70's 3.0 carbureted BMW ( 3 liter 6 cyl or 2 liter 4cyl have the same cc per cyl) has a stock manifold with runners around 1.4 dia. From a design stand point they are very similar- two separate manifolds each having its' own carb using individual runners from a plenum just large enough to get every thing hooked together. They used 2 progressive Weber 32-36, one on each 3 cyl manifold.
That 1.125 gets to about 1 square in. The 1.4 dia of the BMW gets a strong 1.5 sq. in. 50% increase for same size cyl??
On our ford 6 heads of the mid sixties era (170 and 200) have a head I started on back then by cutting off about half the log with a 9 in grinder 8) Changed plans and head layed out in weather all valves rusted tight. casting # went with cut off pieces, but pretty sure it was from an early 200. ANYWAY--think the ports from log to valve are in the 1.2

area and at the time seemed small compared to the old 223 six. intake ports.
Point is down in that port size to cyl disp --Would think cam timing more likely might be the culprit for the bot to mid torque?? Lobe centers??
On the later big log heads the ports vary, but come close to that 1.4 Sq. In. area and these engines do well in the low to mid torque ranges.
Reason for all this is that I am working on individual runner intakes on both a large log 72 head and Mikes alloy head, and chasing every design to get an idea of where to start. The alloy head by the way has a port dia 1.62+ or 1.7-not exactly round. That's BIG for a 200!!
Myway

I just finished individual runners on a 72 head. I machined off the entire intake - pictures below (I hope - first time trying to post pictures)
It's fuel injected but it might give you an idea for an intake.

my way:-The port had a stagnant zone of less than 1.22" of port area downstream of the gasket face according to pge 24 of David Vizards "How to Modifiy Fords S.O.H.C Engines", It was unresponsive to carb, cam and head modifications because of it. The short turn radius has to be a regular cathedral port or apple port to improve things, just the V6 2.8 Chevy or LSIII engines


Adding JB Weld or metal to the floor of the port improved BSFC and mid range torque and didn't hurt power. The port shape and the cam were always very bad matches for the 2 liter engine. The early 1.6 2-bbl versions made proprtionally better power, mid range and peak torque and fuel economy to the 2.0, especially with the factory headers the 1.6 GT ran from 1970-1974. The 1600 2V cam had a perfect lobe 113 degree lobe centers, which gave unfaultering acceleration, especially with its optimzed ignition for that engine.

The other stock SOHC 1300's and 1600's which America didn't get in the Pinto were 106 degrees lobe centers. Then Ford also made some 116 degree center cams for the 2 liter, and it was a dog. All 2 liter cams were carefully crafted by the Germans to cover up poor porting, which was never changed. The gave a good idle, and it masked the negative facets of the head very well. When the EFI 2.0 system is attached, the dead port area is a pefect flow path for the injector, so perhaps the Cologne engieering team designed the 2.0 from the outset for EFI.

67Straightsix... what can I say but props to you man, and Well done. Your wife will love it when your finished.

67Straightsix-Nice workmanship Can appreciate the time involved as my 72 head involved a rough cutting of the majority of the log dia. off. Then some port work and stubs of 1 1/2 dia exhaust tube cut out of elbows formed to fit the somewhat rectangular shape. Used enough of the elbow to get the port angle to about 11 deg.(going to use carbs and not have to large a scoop protrusion) and enough straight to get 2 1/2 in. stub to attach to using 1 1/2 radiator hose. these stubs are unified to the head with stuff called lab metal-a one component JB weld type material. The 1.4+ inside dia. of the exhaust tube smoothed out well with a little help from the lab metal. The log manifold and runners is a story in it's self and developing :roll:
Your runner dia and head flange opening dia. looks bigger than my 1 1/2 O.D. stuff. how large did you get the port in the head casting? Intake valve size?

Like to see Visards article as I still have trouble visualizing that little port working at high RPM.
Gotta catch some more ZZ"s
Thanks all--
Myway

my way":15uozn1g said:

Like to see Visards article as I still have trouble visualizing that little port working at high RPM.
Gotta catch some more ZZ"s
Thanks all--
Myway

Click to expand...

See it on How to Modify Ford SOHC Engines (Pinto/Cortina/Capri/Sierra 1.3- 2.0 litre 1970 to 1982) by David Vizard, published 1984 by Fountain Press.

ISBN 0 86343 9856, Dewy Decimal No 629.2504 Viz




http://www.scribd.com/doc/26804743/How- ... vid-Vizard

First off - xctasy, the amount of information you come up with is amazing! You helped a lot with my design. The two runner to one carb would be
a neat idea for the our 200's. I posted the pictures because I thought splitting the plenums into three separate parts for three two barrels with
the straight runners would be the least restrictive air flow. The runners should have a bit of a venturi effect because they're tapered. The downside
to this design is the carburetor will sit above the hood-line.

The valves size is 150 exhaust - 175 intake. The runner diameter at the head is a little over 1.5" and tapers to roughly 1.75".

67Straightsix":25hhc580 said:

First off - xctasy, the amount of information you come up with is amazing! You helped a lot with my design. The two runner to one carb would be
a neat idea for the our 200's. I posted the pictures because I thought splitting the plenums into three separate parts for three two barrels with
the straight runners would be the least restrictive air flow. The runners should have a bit of a venturi effect because they're tapered. The downside
to this design is the carburetor will sit above the hood-line.

The valves size is 150 exhaust - 175 intake. The runner diameter at the head is a little over 1.5" and tapers to roughly 1.75".

Click to expand...

I wonder if that could be dealt with by using side draft carbs????

Soldmy66":31lnw319 said:

67Straightsix":31lnw319 said:

First off - xctasy, the amount of information you come up with is amazing! You helped a lot with my design. The two runner to one carb would be
a neat idea for the our 200's. I posted the pictures because I thought splitting the plenums into three separate parts for three two barrels with
the straight runners would be the least restrictive air flow. The runners should have a bit of a venturi effect because they're tapered. The downside
to this design is the carburetor will sit above the hood-line.

The valves size is 150 exhaust - 175 intake. The runner diameter at the head is a little over 1.5" and tapers to roughly 1.75".

Click to expand...

I wonder if that could be dealt with by using side draft carbs????

Click to expand...

Yes!, that is the total answer! The only proviso is that sidedrafts have there own space and throttle actuation requirements too. They are't as plentifull as automotive carbs, and any carburettor, down or side draft in 1.125 to 1.65" venturi will always need 3.75 to 5" of space to function and be filitered.

Going back to Ak Miller, there are any number of Constant depression or variable venturi car of motorcycle carbs to use.

Ford Fox and X-shell spring toweres get in the way of side draft air cleaners, but motorcylces have been making 2 to 2.5 hp per cubic inch since the darkages in limited space situations.

Spring tower brace bars (if fitted) hitting the third carb and limited hood height aren't an issue with side drafts.

67Straightsix":30hphn9c said:

First off - xctasy, the amount of information you come up with is amazing! You helped a lot with my design. The two runner to one carb would be
a neat idea for the our 200's. I posted the pictures because I thought splitting the plenums into three separate parts for three two barrels with
the straight runners would be the least restrictive air flow. The runners should have a bit of a venturi effect because they're tapered. The downside
to this design is the carburetor will sit above the hood-line.

The valves size is 150 exhaust - 175 intake. The runner diameter at the head is a little over 1.5" and tapers to roughly 1.75".

Click to expand...

I wonder if that could be dealt with by using side draft carbs????

Click to expand...

if you are going to convert to EFI, you can use three cfi throttle bodies in a side draft individual runner set up, and use a megasquirt controller.

Right on rbohm.

Once you've got a nice intake manifold like the one 67Straightsix has, you can hang on anything to it side draft induction wise. The sky isn't the limit, the spring towers are!

The Megasquirt will work with almost anything if you know the injector type operation. Note a standard V8/V6 Ford CFI uses Bosch injector type. The example here is differetn, as this is the common the Nissan Pathfinder VQ30E 145 hp CFI unit used on 1988-1991 EA 135 hp 3.2 liter and 164 hp 3.9liter engines. And the Geo 3 and 4 cylinder CFI's. The throttle body parts are really a double up of the Chrysler K car single TBi unit. As Spectre engineering found out on the Hot Rod/ Classic Inlines Maverick Nitrous smoke down,

http://www.hotrod.com/features/hrdp-071 ... -maverick/

you can do anything with these internal pressure regulated units. They are similar to the HSC TBI units, same injector. Not the same at all as the Windsor 5.0 V8 or Essex 3.8 V6 CFI

Anyway, care of Robert Cowland from http://www.ozrodders.com/forum/viewtopi ... 5&p=421132

here's what two Falcon EA CFI /Nissan V6 CFI units look like on a 4-bbl V8 intake manifold. They are now SIDEDRAFTS!




Now, truth and reconcilliation time.

A quick note to cover a mistake I made that myway noted, which ties all this info together. .

xctasy":38f8lewa said:

The EAO/Pinto I4 ports were about 1-1/8" or 29 mm at the gasket face,

Click to expand...

Intuitively to myway, something sounded screwy with this. I Found out after checking page 24 again, the Pinto 2 liter port size at gasket face is probably 1.38", or about 35 mm. myway thinks it might be even bigger than that. Its been a while since I had a Pinto 2.0 liter appart, so I couldn't say for sure.

As a comparison, the Cross flow Falcon XD/XE/XF 3.3 and 4.1 head is 1.3" or about 33 mm diameter.

The earlier 1976-1979 Cross flow Falcon XC was 1.574" or 40 mm, the 1971-1974 2V 250 was 1.673" or 42.5 mm


Now, the real kicker is what David Vizard said about his Pinto 2000 automatic on page 23 of the book note in my previous post.

Does a normal engine, which is only required for high performance on the road, require the ultimate in cylinder heads? When talking about the ultimate in cylinder heads, one should consider expense as well as practicality My advice is, if your pocket book will stretch far even for road applications, choose a big-valve head, you
lose nothing in low-end power, but you wlll galn top-end per-formance. (This assumes of course your-enme is cammed in a suitable manner)

Let me give you an example. My normal road-gomg Pinto 2000 automatic uses one of my head configurations which on a flow bench produced a lot more airflow than many current race heads. This engie works fine with the standard torque converter, and produces almost double the horsepower at the rear wheels that the original engine did.

Thls is achieved with head, carburation, cam and exhaust-manifold changes. This should bring home the point that Ford's SOHC engine needs every bit of breathing it can get. While producing this extra power, the engine still met and even surpassed the original emission standards. Moreover, it yields about 4 MPG than it originally did

This rule of strivin g for maximum aiflow should be considered valid only insofar as your finances permit. You can draw the line when weld material must be added to the ports. When you begin building completely new ports, then the expenseis seldom justified for a road machine. You should then look for other more economic ways to improve horsepwer

Click to expand...

That's where Edlebrock was in 1977...adding a better intake manifold to cover over to large stagnant air flow SOHC Pinto intake ports.

On the I6, its significantly easier to generate econmical intake port modifications by welding. Air flow is the key.

I will add this to the ( airflow is key ) I worked with a Big Wheel for almost a year in TN by the Name of Blair Patrick , his Combos generate almost unbelievable HP and Torque Figures given the Constraints of Stock Eliminator Racing Rules , I cant divulge too much as I am sworn to secrecy about his brand / method of Chili ( his term ) , but Velocity and mid lift numbers along with average flow is THE key , NOT Total airflow , Food for Thought

Falconsedandellivery you bring up a good point . Never thought about lift in manifold design . I do think xctacy has it right, a straight runner to the valve on the I6 is the way to go . I've been trolling this site , and have not seen any intakes with long straight runners . Kind of curious to see how it would work.
One thing that keeps nagging at me - the engines that seem to make the most H.P. have a manifold similar to dos10s or Classic Inlines (I do realize these are turbo engines). You guys are making me think to much!

I did the Alk Miller 4 honda carb thing back in 67. It worked great. Later was planning on 6 Quick Silver carbs when they first came out late 70s I think. Couldnt get him to give me a deal on 6 carbs at one. He was giving them away at bike races. Was going to use the existing log to be able to comunicate between runners but under full throttle be a straight shot. Never finished moding the head and sold it to a boater.

FalconSedanDelivery":2evynv8o said:

I will add this to the ( airflow is key ) I worked with a Big Wheel for almost a year in TN by the Name of Blair Patrick , his Combos generate almost unbelievable HP and Torque Figures given the Constraints of Stock Eliminator Racing Rules , I cant divulge too much as I am sworn to secrecy about his brand / method of Chili ( his term ) , but Velocity and mid lift numbers along with average flow is THE key , NOT Total airflow , Food for Thought

Click to expand...

Based on the science, I believe you!

Well, an affirming update for you Faron.

I was watching a Wall of Voodoo video the other day, and since I'm old and my eyesight aint too good, I thought this 69 Buick station wagon was a 1965 Oldsmobile Vista Cruiser.







(the Buick above was so beat up, the swage line was a dent, I thought, sue me!)

After wrongly searching for a Voka Cruiser, I found this....

A Quad Quadrajet 66 Olds Cuttlet, um, Cutlass.

http://www.enginelabs.com/engine-tech/c ... ng-finest/


In this video, Tom Cox said the most amazing thing

about sizing the carb to suit the intake pulses, not the cubic inches.

https://www.youtube.com/watch?feature=p ... a00UNBah18

True wisdom!







The learning project. was what happens when you take a carb signed for large capacity engines, and double or trebble it.

I found that the Closed Plenumb, Siamesed Runner (SR) Venturi on Pair systems, there are idealized venturi area to HP curves, with a critical air speed, The info is for A and B series BMC engines. On a 1435 cc 88 cubic inch Mini A series engine, one IDA 48 made 145hp with 38 mm chokes, and thats a 592 cfm carb at 1.5"Hg, but the engine only consumed 180 cfm at 145 hp.


Similar info for Argentinas TC 3000 engines with the same carb show three times the power, 390 hp at 9500 rpm. It consumed about 500 cfm of air for a carb with a delivery potential of 592 cfm..

Then from 1973 to about 1984, Ford and Holden Group 3 sedan racers would bolt on two for 1184 cfm, and get around 430 asa 308, and about 530 as a 351. A good 351C woulld only comsum 770 cfm of air at 7500 rpm.

Here is the kicker...With just a 390 cfm restrictor plate 4-bbl , A 355 cubic inch NASCAR restrictor plate engine can flow 880 cfm, and then still generate over 5 times the horse power of a 592 cfm carb Mini 1435 88 cube enginewith an open plenumb two venturi per cylinder 4-bbl, despite it flowing less than the Weber IDA 48 2-bbl carb.


IR, port on port carb setups you find on pre 1981 V12 Ferraris, the original 289 Ford GT40's, just don't allow NASCAR style air speeds of 815 feet per second, they like 165 to as little as 60 feet per second in some cases. That means the rstrictor plate NASCAR engines were not so far shy of a 1116 feet per second sonic boom in there 390 cfm carbs.


I found more info on the little 230 hp Holden XU1 today...those split carbs arent 45 Dcoe's, but effectively 3-bbl, ex 2.5 litere 4 cylinder Coventry Climax engine 58 DCO 3 carburetors with huge 47mm chokes 78 thou, 200 micron main jets and 200 air correction jets, was exactly what the 1973 3.3 XU1 used.


So at 6500 rpm, the little 3.3 only needed about 380 cfm, so air speed would have been about 80 feet per second. This compares with 388 to 446 cfm from FSD's 220 hp 250, with an air speed of around 285 feet per second.

The 58 DCOE's are like 3/4 of a 1250cfm Dominator 4500 but with a 2.25" throttles and 1.85" venturis, so that's like 938 cfm at least a t 1.5"Hg, and what...230 hp!

Peak air flow and CFM are not the bees knees.


I'm now aware that Ak Miller and FSD have been merchants of anti matter...with under carbed engines making more power than more expensive carb sytstems.