Conversion from 2BBL to 4BBL / install & match ??

J

j5ball

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I am converting my current (engine 350 CID) 2BBL Rochester 2Jet carb to a Holley 600 CMF 4BBL carb. I just bought a 4BBL Edelbrock intake that is suppose to fit my car. The only numbers on the intake are: P4B. Hopefully that works. I bought a Holley 4BBL carb from a friend. He had it on his 1965 Plymouth Fury II. He is going to a tunnel ram 4x4 setup. Looks awesome. Anyway, the numbers on the carb are: 80457-2. Can I just bolt the carb on top of the intake and be done with it. Or, do I need to adjust the carb (floats) for my engine? I assume I will need to tune the fuel and air screws - but that is just a guess. The carb worked great on my buddies car (I think 427 long block) so I know it currently works. Thanks . . . JIMB
 
If your fuel pump puts out a similar pressure to the original car there is no need to adjust the floats. The idle speed and mixture screws will probably need some adjustment. The P4B is a general Pontiac type manifold very similar to the factory cast iron version.
 
My intake has a piece of metal missing from the middle of where the carb sits. Looks like someone cut a notch out of the cross bar. What is this. Pics on the way
 
There is a notch in the center divider towards the back of the intake, this is normal. If you google P4B you will see pictures of it. It is a way of increasing the plenum volume for increased high RPM performance.
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Thanks. I have to add a spacer to the bottom of my carb so the idle bracket will clear the intake manifold. I see there are spacers with just one big hole and spacers with 4 smaller holes to match the holes on the bottom of the carb. What are the advantages/disadvantage of both? Which one do I want for more ....grrrrrr.... RPMs?
 
The type of spacer will give you more "grrr" depending on all the other parts. Generally speaking an open spacer will help in higher RPM areas and the 4 hole better down on the bottom end. For your engine I would go with either the 4 hole or if you can find it a split one that matches the top of the intake.
 
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