Holly 750cfm
- Thread starter Nick1966
- Start date
8) can you put it on a 200? i would say yes, because if you are willing to do the needed fabrication and engineering to make it work, then anything is possible. is it a good idea? in this case no. just because a thing can be done, doesnt mean it should be done. 750, as noted, is far too much for this engine. if you really want a four barrel carb on the 200, then figure a way to adapt the holley 390 or the autolite 480 cfm carb. both are the maximum size for most 200 builds. and by the way, xecute did have a drawing posted up once about adapting a four barrel carb to our little sixes. he might be encouraged to put it back up again, or at least link to the thread it was on.(it has been a while since i saw it, and i have had other things on my mind recently so i dont remember the thread).
200 cubic inch engine is probably okay with a vac sec 750 cfm carb as long as you use a Powerband style intake manifold. Trans Am 302 Mustangs ran two 1050 CFM Dominator carbs with 13.2 cubic inches per square inch of venturi. A mechanical secondary 450 or 450 double pumper, which has 4.908 sq in of venturi area, might do better on a 200. Any less than 30 cubic inches per square inch of venturi area, the carb is not likely not to work. A 390 cfm 4-bbl will work on a 121 cubic inch Ford engine, and the stats for that are 3.546/121, or 34.375 cubic inches per square inch of venturi. The PVCR's and squirter jets and overall jetting would need to be reworked, a low value power valve and some hard work on the idle air correctors and bleeds.
There is a well defined venturi area to cubic inches engine capacity relationship that Weber put into the public back in the 1930's
Americans tend to use CFM verses Cubic Inch Displacement (cid). The relationships of each define how much or how little carburation you can get away with.
I've interigated all the known combinations of Weber and American Holley/Autolite/Motorcraft/Rochester/Bendix~Stromberg/Carter style carb instillations with their engines, and went through those from 1996 to date, its an ongoing thing. I posted that as Restrictor Plates 27_11_2011 on one particular post.
See viewtopic.php?f=1&t=66999&p=528787#p528787
Smallest carb for to function is about 221 cubic inches per square inch of venturi, which you find on a 250 Ford six, one of the worlds most restricted carb engines around
See the following Autolite 1100 Sizes and Applications
1.00 Venturi (120 CFM): 144 ThriftPower Six is 183 cid per square inch of venturi
1.10 Venturi (150 CFM): 170 ThriftPower Six is 179 cid per square inch of venturi
1.20 Venturi (185 CFM): 200, 250 Six is 177 to 221 cid per sqaure inch of venturi
1.29 Venturi (210 cfm) 223,262,240 and 250 from 1963-1969, that is 170,200,183 and 191 cid per sqaure inch of venturi respectively
Biggest carb for an engine I've seen would have been the early 239 cid Lamborghini Countach LP400, with a 325 to 375 hp 3.9 liter V12 with six double barrel Webers which was about 11.4 cubic inches per square inch of venturi. It reved to about 8000 rpm, and had little torque below 5000 rpm, and there were two types of screemer cam for it. If you copied that set up, you'd find a 3310 part number 750 cfm vac sec 4-bbl has about 5.938 square inches of venturi area, and it would work well with as little as 68 cubic inches, perhaps your neigbours frog eye Austin Healy Sprite would take it if he shoved in a 326 degree BMC tuning cam.
Generally,most Ferrari 400, Ferrari BB512, BB 365 Ferraris and the wildly modifed stock 240 I6's such as the Preparation H 310/600 thou lift 90 over lap triple IDA 48 Weber performance machines like 20 cubic inches per square inch of venturi, but thats where you have port on port induction.
The 2-bbl and 4-bbls cant work well with less than 41 cubic inches per square inch of venturi, so for a 5.938 sq in 4-bbl 750cfm Holley, it would ground out about 240 cubic inches. Factory mechanical secondary carbs, like the old 1980 to 1982 250 V6 Buicks and some 1980 to 1985 Australian 253 V8's ran a 725 cfm Rochester 4M Quadrajet, so that's about how far you can strectch the friendship. A few 725 cfm Carter AVS 4-BBLS found there way on to 250 cubic inch Hemi Valiants in Australia, so anythings possible
If you have a 285 degree cam shaft with 550 thou lift, and a 12:1 compression ratio, running to 8000 rpm, then a single 4-bbl 750 on the right intake manifold might do something, but you'd have to do something brillant to a log head to get that to work.
I've seen big 460s make 420 hp with just a 500 cfm 2-bbl Holley, but loose 145 hp on a 1050 Dominator. A 289 with 500 cfm 2-bbl can make 350 hp, but loose 200 hp on a quad IDA 48 carb. But there are NASCAR's which could make 650 hp with just a 390 cfm 4-bbl. So big carbs make power, but little ones can still make quite a lot. One TC3000 car in Argentina can make 395 hp with just one IDA 48 carb, from just 183 cubic inches. If you tune the engine to suit the carb, you can work wounders
There is a well defined venturi area to cubic inches engine capacity relationship that Weber put into the public back in the 1930's
Americans tend to use CFM verses Cubic Inch Displacement (cid). The relationships of each define how much or how little carburation you can get away with.
I've interigated all the known combinations of Weber and American Holley/Autolite/Motorcraft/Rochester/Bendix~Stromberg/Carter style carb instillations with their engines, and went through those from 1996 to date, its an ongoing thing. I posted that as Restrictor Plates 27_11_2011 on one particular post.
See viewtopic.php?f=1&t=66999&p=528787#p528787
I prepared a calibration model, Restrictor Plates 27_11_2011.jpg, and used it to develop my NCHO-6V intake, the NCHO-2V intake and now the NCHO-4V intake.
It's based on the power curve verses carb venturi area, not carb throttle area. The factor to look at is "Cubic inches per sq in of carb venturi" in column T
Here are some screen dumps.
A really restricted engine will have 1 sq in of carb area to 300 cubic inches of engine. Example was the old Ford Zephyr 155 cubic inch six as used in the 1961 AC Ace in line 86. That is more restricted than a WRC or Restrictor plate equiped NASCAR.
The WRC, a two liter turbo engine, has a 35 mm plate giving 81.8 cubic inches per square inch of induction. The old Winston Cup NASCARS were running 127 to 146.
The NASCAR restrictor plate engines are less restricted than any stock 1-bbl Falcon Six engined Ford.
A really unrestricted engine is the Lamborghini LP 400, with about 11 cubic inches of engine per sqaure inch of carb.
A triple carbed 250 with 1904 Holleys is on the lower end of restriction, but still as restricted as a WRC rallye car. And more restricted than a 1970 Pinto 2000 with a 5200 Holley Weber 2-bbl. (71 cubes per square).
The European 88 hp 1600 GT Pinto engine (97 cubes for 88 pintos, um, ponies) had less cubes per square inch of venturi than a 351 4V Boss/Phase iii engine (57 vs 59). In terms of specific out put, the production lines hotest Cleveland still made more gross or net power per cube. (Rated at 330 hp, but known to give 350 hp net, and 380 hp gross)
Smallest carb for to function is about 221 cubic inches per square inch of venturi, which you find on a 250 Ford six, one of the worlds most restricted carb engines around
See the following Autolite 1100 Sizes and Applications
1.00 Venturi (120 CFM): 144 ThriftPower Six is 183 cid per square inch of venturi
1.10 Venturi (150 CFM): 170 ThriftPower Six is 179 cid per square inch of venturi
1.20 Venturi (185 CFM): 200, 250 Six is 177 to 221 cid per sqaure inch of venturi
1.29 Venturi (210 cfm) 223,262,240 and 250 from 1963-1969, that is 170,200,183 and 191 cid per sqaure inch of venturi respectively
Biggest carb for an engine I've seen would have been the early 239 cid Lamborghini Countach LP400, with a 325 to 375 hp 3.9 liter V12 with six double barrel Webers which was about 11.4 cubic inches per square inch of venturi. It reved to about 8000 rpm, and had little torque below 5000 rpm, and there were two types of screemer cam for it. If you copied that set up, you'd find a 3310 part number 750 cfm vac sec 4-bbl has about 5.938 square inches of venturi area, and it would work well with as little as 68 cubic inches, perhaps your neigbours frog eye Austin Healy Sprite would take it if he shoved in a 326 degree BMC tuning cam.
Generally,most Ferrari 400, Ferrari BB512, BB 365 Ferraris and the wildly modifed stock 240 I6's such as the Preparation H 310/600 thou lift 90 over lap triple IDA 48 Weber performance machines like 20 cubic inches per square inch of venturi, but thats where you have port on port induction.
The 2-bbl and 4-bbls cant work well with less than 41 cubic inches per square inch of venturi, so for a 5.938 sq in 4-bbl 750cfm Holley, it would ground out about 240 cubic inches. Factory mechanical secondary carbs, like the old 1980 to 1982 250 V6 Buicks and some 1980 to 1985 Australian 253 V8's ran a 725 cfm Rochester 4M Quadrajet, so that's about how far you can strectch the friendship. A few 725 cfm Carter AVS 4-BBLS found there way on to 250 cubic inch Hemi Valiants in Australia, so anythings possible
If you have a 285 degree cam shaft with 550 thou lift, and a 12:1 compression ratio, running to 8000 rpm, then a single 4-bbl 750 on the right intake manifold might do something, but you'd have to do something brillant to a log head to get that to work.
I've seen big 460s make 420 hp with just a 500 cfm 2-bbl Holley, but loose 145 hp on a 1050 Dominator. A 289 with 500 cfm 2-bbl can make 350 hp, but loose 200 hp on a quad IDA 48 carb. But there are NASCAR's which could make 650 hp with just a 390 cfm 4-bbl. So big carbs make power, but little ones can still make quite a lot. One TC3000 car in Argentina can make 395 hp with just one IDA 48 carb, from just 183 cubic inches. If you tune the engine to suit the carb, you can work wounders
The final NCHO-4V, a 4-bbl 6PT adaptor, is a two part deal based on two adaptors. The base adaptor is the NCHO-6V triple carb adaptor I made and discussed in the Hardcore forum.
The top adaptor is like this
The upper runner intake development was started off by a post powerband made on Saturday July 14, 2012
in "4Bbl instead of 3X 1Barrels?."
The lower adaptor base to the log is the NCHO-6V three 2-bbl throttle body system I described in the hardcore section, which can fit three carbs, 2-bbl Downdraft Weber, Downdraft Holley Weber 5200/5210/6200/6500/6510/6520, Downdraft Holley 2300 series and the Aisin variable venturi downdraft.
The six port lower manifold developement was out lined in these three posts.
Firstly "Making a Low rpm Triple 350 cfm carb setup " on viewtopic.php?f=5&t=31668
Secondly "In honour of Linc's 200: ITZOLD 200 6v" on viewtopic.php?f=5&t=65023
and Thirdly "side draft carbs on log head "....
The top adaptor is like this
http://fordsix.com/forum/viewtopic.php?f=1&t=70514&p=540960#p540960
As for me, the following are basic Paint alterations, but show the basic idea I tried to convey with as few links as possible
The 90 degree turned air cleaner is either a dual snorkel version of the cut and shut stock 3.3 item from the 80's, or the common Cobra item
The upper runner intake development was started off by a post powerband made on Saturday July 14, 2012
in "4Bbl instead of 3X 1Barrels?."
The lower adaptor base to the log is the NCHO-6V three 2-bbl throttle body system I described in the hardcore section, which can fit three carbs, 2-bbl Downdraft Weber, Downdraft Holley Weber 5200/5210/6200/6500/6510/6520, Downdraft Holley 2300 series and the Aisin variable venturi downdraft.
The six port lower manifold developement was out lined in these three posts.
Firstly "Making a Low rpm Triple 350 cfm carb setup " on viewtopic.php?f=5&t=31668
Secondly "In honour of Linc's 200: ITZOLD 200 6v" on viewtopic.php?f=5&t=65023
and Thirdly "side draft carbs on log head "....
http://fordsix.com/forum/viewtopic.php?f=5&t=69515
And my Aisan VV carbed prototype log, which fits the Classic Inlines head, the log head, and allows full emission control EGR and air conditioning to fit, fits the tall 250 engine under the Fox body hood. It works best with the later iron exhasts, the aftermarket industry still hasn't gotten its head around emission with the 3.3 and 4.1 combos yet.
And the 1984 to 1990 twin carb Toyota Corolla 1452 cc 3A HU intake and carb set up I based it on.
http://tercel4wd.com/viewtopic.php?f=8&t=1383
http://www.youtube.com/watch?v=OMD0praeb3g
in "4Bbl instead of 3X 1Barrels?."
xctasy":2fmfe1x2 said:xctasy":2fmfe1x2 said:When Lincs 200 came up with a Sidewinder external ducting to the out log like this,
,
I knew I could put a 2-bbl on the log and get it flowing well enough for port EFI.
If you slapped a proper 4180 or 4160 600 cfm 4-bbl on the Offy, and had some tubes going to the outer four cylinders via the secondary circuit of that carb, you'd be making serious power.
So we take a late head like this
and slap a 4-bbl to 2-bbl adaptor on the 1-bbl adaptor, and then funnel the secondary 2-bbl out to the outher ports.
And here are the basics in alloy.
xctasy":1wasy3ng said:in "4Bbl instead of 3X 1Barrels?."
xctasy":1wasy3ng said:xctasy":1wasy3ng said:When Lincs 200 came up with a Sidewinder external ducting to the out log like this,
,
I knew I could put a 2-bbl on the log and get it flowing well enough for port EFI.
If you slapped a proper 4180 or 4160 600 cfm 4-bbl on the Offy, and had some tubes going to the outer four cylinders via the secondary circuit of that carb, you'd be making serious power.
So we take a late head like this
and slap a 4-bbl to 2-bbl adaptor on the 1-bbl adaptor, and then funnel the secondary 2-bbl out to the outher ports.
And here are the basics in alloy.
this was the post i was looking for.
Thought so.
The adaptor base is just a flat piece of plate, and I redid the top so it can fit any carb, 1, 2, 3 1-bbls, or 1, 2 or 3 2-bbls, or 1 4-bbl.
I started out with the stock 1981 Fox carb on my old 1963 to 1968 Aussie C1 spec closed chamber head, and it went from that. Everything is now under hood, fits stock emissions, uses stock linkages.
With the right upper adaptor, an underhood 4-bbl is dead easy.
The adaptor base is just a flat piece of plate, and I redid the top so it can fit any carb, 1, 2, 3 1-bbls, or 1, 2 or 3 2-bbls, or 1 4-bbl.
I started out with the stock 1981 Fox carb on my old 1963 to 1968 Aussie C1 spec closed chamber head, and it went from that. Everything is now under hood, fits stock emissions, uses stock linkages.
With the right upper adaptor, an underhood 4-bbl is dead easy.
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