I’m building a 200 cubic inch.short block is a 1976 - 30 over-head is a 1979 big log competition type valve job and milled 60.. Howard’s 2800280 cam- stainless headers- pertronics distributor- . My question is which carburetor should I use- I don’t particularly like a Weber. I like the holley 350 2 barrel. But is it too big?? It’s a daily driver and I don’t want to mill and fill the intake- also I need info on where to purchase a nice billet adapter would like helpful comments- please don’t tell me I need an aluminum head or tons of machine shop work.
All Small Six Carburation
- Thread starter Spike56
- Start date
This relates to all small sixes
Holleys are good and cheap. Although I prefer a Weber for a street driven vehicle, easy to tune and once right you do not have to touch it, plus good on fuel.
DON
Famous Member
I am going to use a Holley 2300, 350cfm on my engine. .456 lift, 274 duration, roller rockers, modified large log head and 10.2/1 compression. And if you look at flow charts for modified heads, it’s right there. It might be a hair starved on very top end but I don’t plan on going over 5k rpm. I will say I have a Webber 32/36 progressive for a stock engine with HEI ignition and it worked great! It was pre tuned for my engine when I bought it. Helped drivability a lot! I am using the Holley because I am familiar with rebuilding them and tuning them. A 350 is plenty of carb for a basically stock engine 
Linkage hook up for the Webber is easier, the linkage is on the side, the Holley linkage will be on the front, a cable conversion would be easiest. I am hoping to figure out a mechanical linkage that will make the 90degree turn
Check Vintage Inlines for the adapter
Linkage hook up for the Webber is easier, the linkage is on the side, the Holley linkage will be on the front, a cable conversion would be easiest. I am hoping to figure out a mechanical linkage that will make the 90degree turn
Check Vintage Inlines for the adapter
TrickSix
Well-known member
As usual, more power means more money. Getting the most out of a two barrel carb requires major machine shop modifications on the intake to mount it. A 2 into 1 adaptor makes mounting it easier and cheaper, but doesn't flow as well, and still needs a lot of line and linkage mods. A 1101 carb is pretty much an easy bolt on, and flows better than the stock 1100, but not as well as a 2 barrel. Cheap to try though, if you're not happy with it you can always spend more money later.
the 350 '7448' Holley is universally available and a good carb for tweaking a new build. Parts and upgrades are same as universal 4150 4 Bbl with plenty of info. Interestingly - the 500 CFM 2300 '4412' version is usually less expensive , maybe more common?.
I've used 350 and 500 CFM 2300's on various small block six builds. 350 works well on mild builds but definitely more carb than most will ever need. Trying a 500 on a mild small six produced eye-watering rich conditions hard to remove. On a performance built 250 , the 500 was adequate but without intake mods don't see the point.
For best actual road drivability if not performance, the progressive 2 Bbl or progressive multiple carbs' on a built small six should be considered. Weber and similar Holley/Weber progressive 2Bbl's are rated up through 300CFM but small primary adds MPG with better low throttle response and 'kick' when secondary opens.
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practically - the later cable over the valve cover Pedal setup used on Stang/Maverick sixes makes swapping carbs simpler.
- Adapters and tall carbs have air cleaner clearance problems on most cars.
- quality fuel pressure device recommended.
- mounting 2300's with fuel bowl directly above exh./Headers not recommended.
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2 X 1 Adapters work fine for using different purpose carbs' on the small six but need much-mentioned mod/fab of intake 'manifold' to enable big CFM flow carbs... . Nicest 2 X 1 adapter found was from VI , well machined for function.
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daily driver wagon has Maverick 170 / @9.5:1 SCR milled/worked '77 head / Headers / H-W 5200 (32/36) carb on $15 2X1 adapter / T5 / tube radio. Runn'n great over 10 years...
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I've used 350 and 500 CFM 2300's on various small block six builds. 350 works well on mild builds but definitely more carb than most will ever need. Trying a 500 on a mild small six produced eye-watering rich conditions hard to remove. On a performance built 250 , the 500 was adequate but without intake mods don't see the point.
For best actual road drivability if not performance, the progressive 2 Bbl or progressive multiple carbs' on a built small six should be considered. Weber and similar Holley/Weber progressive 2Bbl's are rated up through 300CFM but small primary adds MPG with better low throttle response and 'kick' when secondary opens.
.
practically - the later cable over the valve cover Pedal setup used on Stang/Maverick sixes makes swapping carbs simpler.
- Adapters and tall carbs have air cleaner clearance problems on most cars.
- quality fuel pressure device recommended.
- mounting 2300's with fuel bowl directly above exh./Headers not recommended.
.
. .
. .
. .
. .
2 X 1 Adapters work fine for using different purpose carbs' on the small six but need much-mentioned mod/fab of intake 'manifold' to enable big CFM flow carbs... . Nicest 2 X 1 adapter found was from VI , well machined for function.
. . .
daily driver wagon has Maverick 170 / @9.5:1 SCR milled/worked '77 head / Headers / H-W 5200 (32/36) carb on $15 2X1 adapter / T5 / tube radio. Runn'n great over 10 years...
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Last edited:
twentyover
Well-known member
Provided sans comment
Hog out the large log intake bore then make an aluminum small base (eBay) Rochester 2 barrel (Marine) adapter.
The throttle bores are closer together on the Rochester small base carbs than the Autolite or Holley carbs.
This way you won't take the risk of having a cast iron brazed head that is cracked.
I would install a Weber Carb + adapter before I took the risk of having the head being filled, milled + cracked.
The intake bore can be enlarged along with matching a Weber adapter to the enlarged intake bore.
Not all large log heads are as suitable for the mill + fill procedure.
The flat top of the intake log on the D7 head may be a good candidate for a shop with a furnace and an expert welder.
The D8 intake log is not flat at all.
The throttle bores are closer together on the Rochester small base carbs than the Autolite or Holley carbs.
This way you won't take the risk of having a cast iron brazed head that is cracked.
I would install a Weber Carb + adapter before I took the risk of having the head being filled, milled + cracked.
The intake bore can be enlarged along with matching a Weber adapter to the enlarged intake bore.
Not all large log heads are as suitable for the mill + fill procedure.
The flat top of the intake log on the D7 head may be a good candidate for a shop with a furnace and an expert welder.
The D8 intake log is not flat at all.
Wayne clark
Well-known member
I was going to second the Vintage Inline adapter . I run a 2300 Sniper & Hyperspark dist for timing control along with a Sn89 Paxton Supercharger on.my 67 stock Small log headed 200 . Personally I don't think you can beat the 2300 Snipet for power & performancethe 350 '7448' Holley is universally available and a good carb for tweaking a new build. Parts and upgrades are same as universal 4150 4 Bbl with plenty of info. Interestingly - the 500 CFM 2300 '4412' version is usually less expensive , maybe more common?.
I've used 350 and 500 CFM 2300's on various small block six builds. 350 works well on mild builds but definitely more carb than most will ever need. Trying a 500 on a mild small six produced eye-watering rich conditions hard to remove. On a performance built 250 , the 500 was adequate but without intake mods don't see the point.
For best actual road drivability if not performance, the progressive 2 Bbl or progressive multiple carbs' on a built small six should be considered. Weber and similar Holley/Weber progressive 2Bbl's are rated up through 300CFM but small primary adds MPG with better low throttle response and 'kick' when secondary opens.
.
practically - the later cable over the valve cover Pedal setup used on Stang/Maverick sixes makes swapping carbs simpler.
- Adapters and tall carbs have air cleaner clearance problems on most cars.
- quality fuel pressure device recommended.
- mounting 2300's with fuel bowl directly above exh./Headers not recommended.
.
.
.
.
.
2 X 1 Adapters work fine for using different purpose carbs' on the small six but need much-mentioned mod/fab of intake 'manifold' to enable big CFM flow carbs... . Nicest 2 X 1 adapter found was from VI , well machined for function.
.
daily driver wagon has Maverick 170 / @9.5:1 SCR milled/worked '77 head / Headers / H-W 5200 (32/36) carb on $15 2X1 adapter / T5 / tube radio. Runn'n great over 10 years...
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I used that thing in the beginning with the stock points dist & stock single exhaust . Far & away the best power adder I've found by itself. .
Frank, what model number carb would that be?? Most I find are the 500 cfm types. Thanks
I pulled this for a '71 Chevy truck, 307 V8 and this is the carb. Chose this year and model because I still have the carb off of mine(though the trucks been gone for 30 years). this is the carb I'm referring to. Mounting base bolt spacing is 3 3/8" x 1 7/8", and the big bore 1 barrel filters fit the top.
I'm not selling you on this carb- Ford guys aren't familiar with Rochester as a rule. But this exact carb had many millions of factory vehicle equipped with it from 1955 to the '80's, the majority of small GM 8's up to and sometimes including the 350. My '71 C10 with the 307 got 18 mpg.
Fortunately we have many good options for carb upgrades Spike56, so thanks to all the Ford six enthusiasts and their innovations and abilities. For me, info on the Rochester is beneficial and will be for many others that are on a budget also since you can do the mods to mount it yourself. And that it can use the air cleaner that you probably already have is a cost savings also. I had been interested in a similar option, the Carter BBD, but don't know how it compares to the Rochester as far as fitment, linkage, air cleaner other details. So far the Rochester is looking pretty good to me and is convenient to order from Rockauto. Nice to hear about your project.
There are lots of new large base Rochester marine 2 jet carbs on eBay for as little as $89.99.
Some have extra jets included.
I am planning on hogging out my large log intake bore even more than it is then building an 1/8" steel carb box with a removable top that bolts to my D7 head.
Some have extra jets included.
I am planning on hogging out my large log intake bore even more than it is then building an 1/8" steel carb box with a removable top that bolts to my D7 head.
I was going to make a 4" wide, 5" or 6" long, 1" high box out of 1/8" steel. It would have a removable top.Just for my knowledge, can you describe what kind of box you are talking about
The bottom of the box would have a cut out that matched my enlarged large log intake bore.
Two bolts would attach the box onto the head.
The top would have gasket and be attached with machine screws.
The top would be cut out to match a large base Rochester 2Jet 1/2" phenolic spacer that I would use on top of the box.
I could weld four 5/16" nuts under the 1/8" plate top or install + tack weld four 5/16" bolts from the bottom of the top to hold the carb. on.
The purpose is more CFM using a large base Rochester 2 Jet to an enlarged inlet bore large log carb adapter.
I have have been running a DIY aluminum small base 2V to enlarged large log carb adapter for a few years.
It works great. The first time I ran it at higher RPM WOT it blew the guts out of my old 2" turbo muffler.
I have have been running a DIY aluminum small base 2V to enlarged large log carb adapter for a few years.
It works great. The first time I ran it at higher RPM WOT it blew the guts out of my old 2" turbo muffler.
Evening folks, anybody want to opine on using a motorcraft 2100 w/ 1.21 venturi for my 200 build. I also have a 78 large log that will be utilized. Again I must remind all that I am trying to acquire the parts for a good little sleeper street rod, and I'm a noob.
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