2 to 4 barrel intake manifold

GoodEnuf

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On a 361 with a 4 barrel carb running an adapter on a 2 barrel stock cast iron manifold, would there be an appreciable power increase to switching to a 4 barrel aluminum intake manifold?

I got a free Holley 4 barrel carb from a co-worker but my 361 has the stock 2 barrel intake manifold. Would it be worth switching to something like the weiand 8008 4 barrel intake manifold? It has cast iron heads and stock cam. Trying to get a parts list together for the spring.
 
Don't recommend using a two to four BBL adapter, they seldom work well. There are lots of 383 4BBL manifolds around, if you are on a budget go that route and that manifold is a bolt on. A lot of the 2BBL engines were single exhaust that was fairly restrictive, so the performance gain is limited. A Carter AFB will bolt to most of the 383 manifolds but the Holley will fit the later manifolds that were set up for a 4160 Holley.

Dave
 
Don't recommend using a two to four BBL adapter, they seldom work well. There are lots of 383 4BBL manifolds around, if you are on a budget go that route and that manifold is a bolt on. A lot of the 2BBL engines were single exhaust that was fairly restrictive, so the performance gain is limited. A Carter AFB will bolt to most of the 383 manifolds but the Holley will fit the later manifolds that were set up for a 4160 Holley.

Dave

Thanks, my stock exhaust was a single. However it was basically non existent so I fabricated a 2.5" dual exhaust.

I have been searching around me for a local 383 4 barrel intake but have not had luck so far finding one. Everyone seems to be a Chevy guy around me ha.
 
Lots of good used Edelbrock Performer intakes available. Mate the intake with a 1406 or 1906 carb and you'll be in business. Good luck!
 
upload_2020-9-14_19-44-31.png
 
Don't recommend using a two to four BBL adapter, they seldom work well. There are lots of 383 4BBL manifolds around, if you are on a budget go that route and that manifold is a bolt on. A lot of the 2BBL engines were single exhaust that was fairly restrictive, so the performance gain is limited. A Carter AFB will bolt to most of the 383 manifolds but the Holley will fit the later manifolds that were set up for a 4160 Holley.

Dave
Depends on the application. I’ve used them since the 80’s and if you use a quality old one you can get a pretty good idea if you’ll like the 4bbl or not. My 69 has been running one since the first week I bought it. The 1 barrel on off switch just sucked and I needed it running reliably. Slapped on the 2 to 4 adapter w a 600 Holley as I looked for a nice cheap small block intake. I found a nice 68 340 iron one for almost free and I’ll get around to putting it on once I do the motor. I guess what I’m saying is if it has a power increase it won’t be a revelation. A 4bbl intake will just make it a less hokey installation.

2 to 4 adapter should be temporary. Mines been on 4 years now so I’m violating my own rule LOL!

Go for it !!!!
 
I concur on watching for a used manifold on eBay or similar. The 361 is basically a smaller 383 on the "low-deck" B block archintecture, 413 and 440 being on the "raised-deck" B block architecture, for clarification. The 1967 and prior factory intakes would have the "small pattern" AFB mounting with a smaller hole in the OEM air cleaner base. The 1968 and later factory intakes would have the "Holley 4160 mounting" and the larger hole in the OEM air cleaner base plate, unless the engine came factory-equipped with a Holley 4160 4bbl (as the '67 New Yorker 440/350 did).

Good luck on your project!
CBODY67
 
Take care of that exhaust FIRST! I just installed a dual exhaust setup, very stock to the year, which neatly DOUBLED the 2.25 inch diameter single exhaust and the resultant cross sectional area. This has improved the gas mileage by about 1.5 mpg. You will also want to change the distributor for a 4 barrel carb, and use hotter plugs to assure good combustion of the extra fuel you'll be dumping into those cylinders.

I'm contemplating a LARGER 2-barrel rather than a 4 barrel carburetor eventually, but not TOO much larger. The Stromberg WWC now serving my 383 gives it a good 350 CFM, which I might some day increase to a 500 CFM Holley. I'm in NO hurry to take this step though, as even this really warrants more modifications, such as a different cam......

Optimize what you have. Its usually better that way.
 
Take care of that exhaust FIRST! I just installed a dual exhaust setup, very stock to the year, which neatly DOUBLED the 2.25 inch diameter single exhaust and the resultant cross sectional area. This has improved the gas mileage by about 1.5 mpg. You will also want to change the distributor for a 4 barrel carb, and use hotter plugs to assure good combustion of the extra fuel you'll be dumping into those cylinders.

I'm contemplating a LARGER 2-barrel rather than a 4 barrel carburetor eventually, but not TOO much larger. The Stromberg WWC now serving my 383 gives it a good 350 CFM, which I might some day increase to a 500 CFM Holley. I'm in NO hurry to take this step though, as even this really warrants more modifications, such as a different cam......

Optimize what you have. Its usually better that way.


I didn't think about using hotter plugs. Why does the distributor need to be changed? I'll be using a hall effect points eliminator conversion kit in the distributor.
 
4bbls had a bit higher compression, 9.2 vs 10.0 in the case of the '66 383 2bbl, for example. In '66, the 383 2bbl had the 252 degree cam, which had its roots (timing event wise) with the first B/RB engines, including the 2x4bbl 350cid Fury in '58) whereas the 383 4bbls had the then-new 256/260 cam of the '66 440/350. The 256 cam became std on 2bbls a few years later. A bit more duration, but a good bit more lift (approx .425" vs .390" advertised).

Usually, the 2bbl '66s had J-14Y Champion spark plugs. The 4bbls had J-10Y Champions, by comparison. But anything in that heat range spread can work, from my experiences, so long as the ceramic insulator does NOT get chalky white in color (indicating "too warm").

I'm stating factory specs, but some might have other orientations from their own experiences.

A 4bbl can be neat to have, but once you have one, you might discover that unless you use WOT a good bit, it can be more "show" than really needed for what you're doing. With any power increases being past the 2500rpm range (which is about 60mph on the highway for a 2.76 rear axle ratio Chrysler).

BUT, getting rid of that adapter with a good 4bbl intake can make things just work better all the way around. Carb linkage, kickdown linkage, and the divorced automatic choke are the main areas that could benefit, typically, by getting things back to a more normal situation, I suspect.

Just some thoughts,
CBODY67
 
4bbls had a bit higher compression ....

Usually, the 2bbl '66s had J-14Y Champion spark plugs. The 4bbls had J-10Y Champions, by comparison. But anything in that heat range spread can work, from my experiences, so long as the ceramic insulator does NOT get chalky white in color (indicating "too warm").

....

A 4bbl can be neat to have, but once you have one, you might discover that unless you use WOT a good bit, it can be more "show" than really needed for what you're doing. With any power increases being past the 2500rpm range (which is about 60mph on the highway for a 2.76 rear axle ratio Chrysler).

Just some thoughts,
CBODY67

You sure you don't have the Champion spark plug numbers turned around? I THINK the J-10Y is for the 2 barrel motors, with the J-14Y for the 4bbl. Dig this! I inherited some J-11Ys with some old heads I scored locally this summer...

Look at P 8-70 of the FSM for the 2bbl:
upload_2020-9-17_23-47-36.png


I know Mathilda sure likes the lower numbered plugs, and tge NOS ONES BEST!
 
When we got the '66 Newport 2bbl when it had 7100 miles on it, when the new '67s came out, when I pulled the plugs out the first time, it had J-14Y Champions in it. When we got the '72 Newport 400 2bbl new, it had J-13Y Champions in it.

One reason for the colder plugs with the 4bbl motors was, as I read a good while back, was that the colder plugs would be less succepible to contributing to detonation at WOT on non-premium fuels (think law enforcement fleets which got their fuel from a common tank, usually "regular" grade). Which could also be why some 4bbl engines only had about 32 degrees total timing in the distributor, rather than the 38 degrees that the 2bbl usually had.

When I got my '70 Monaco 383-4 "N" car, I knew about the colder plugs for the 4bbls, but I also knew I would not be at WOT all that much. It had gotten a tuen-up at the local Chrysler dealer before I bought it used, with 83K miles on it. It had the colder plugs in it. In normal use, they didn't appear to be "not hot enough" to keep the ceramic clean. Ar that time, I would have suspecte that a plug 4 heat ranges colder would have looked different, but they really didn't. But then they were probably looking like a good "extended gap" plug should. Running hot enough at lower loads to stay clean (in a motor that was not running too rich and not using a lot of oil), yet being cold enough to not cause overheating of the tip and contribute to a possible detonation issue at WOT.

In general, it's been my observation that, over the life of the B/RB engines, the "high performance 383 4bbls" got the colder plugs from the factory (historically J-10Y Champions) and the "normal/consumer" 2bbls for the warmer plugs from the factory (historically J-14Y Champions for the pre-emission-era 383s).

Now, the term "High performance 4bbls" is most likely in comparison to the 2bbl motors. Rather than engines as the 383/335 vs the 383/325 engines per se. As the 383/330 "N" in a C-body had the 256/260 cam rather than the 268/284 cam of the 383/335. Check the SAE specs for where the 268/284 cam really was installed, as a Challenger 383 "N" would get the 256 cam, but a Challenger R/T 383 "N" would get the 268/284 cam.

Just my experiences,
CBODY67
 
Your experience is Golden Lore to me, which is why I love reading it. I want to take a nice Saturday morning when the brats aren't hanging on me to take total timing data for Mathilda's plant, then get one of those nice limiter plates from Mancini or another reputable vendor so that I can set the mech advance in steel, if not stone. That will nail down one more floating variable in anticipation of pulling/replacing/re-furbishing the heads and a possible cam replacement. I'm not likely to do the latter unless there has been some serious degradation of the current shaft, but its always good to know what one is working with and what to do with it.
 
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