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Two or Four Barrel on a Chevy 265

14K views 7 replies 8 participants last post by  junior stocker 
#1 ·
I have a 1956 Chevy 265 engine that I am about to replace the intake and carb on. I believe the engine originally had a two barrel carb on it. It is currently running a four barrel that is too big; an 800 cfm.

Can I run a Quadrajet four barrel on this, say a 640 cfm, or should I go with a two barrel?

I don't have a two barrel carb and intake so I am not wanting to spend any more money than I have to. I am real sure this engine came out of a 1956 Chevy car. I have pictures of the engine being put in the car dated Oct. 1956.
I have a friend how says they had a 283 in 1956 and this engine is not a 265. Not really believe this.

Also, the four barrel and intake that I have is from a mid to late 60's 350 engine. Will this intake fit on a 265? I don't know how many small block parts will interchange. The newer intake has a place for a choke thermostat that I believe will help with starting and running.

Some advice and help with this project would be greatly appreciated.

Thanks.
 
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#5 ·
All 1955 (265), 1957 - 1968 (283), 1962 - 1968 (327) 2-barrel and 4-barrel intake manifolds will interchange regardless of engine size. The 1955-1968 2-barrel and 4-barrel intake manifolds can be identified by the oil fill tube next to the thermostat housing. The 1969-up manifolds do not have a oil fill tube on the intake manifold.

Carburetors for those manifolds will be a Rocherster 2GC 2-barrel, a Carter WCFB 4-barrel or a Rochester 4GC 4-barrel. Those 4-barrel carburetors are rated at 500 CFM .
 
#7 ·
Can I run a Quadrajet four barrel on this, say a 640 cfm, or should I go with a two barrel?

I don't have a two barrel carb and intake so I am not wanting to spend any more money than I have to. I am real sure this engine came out of a 1956 Chevy car. I have pictures of the engine being put in the car dated Oct. 1956.
I have a friend how says they had a 283 in 1956 and this engine is not a 265. Not really believe this.


QUOTE]

Yes, you can use a Q jet on the 265. The CFM of the carb will be around 750, but that is a maximum CFM. The beauty of the Q jet design is it will only supply the airflow needed for that particular engine. The small primarys deliver great throttle response and great mileage too. It will fit on a late 60's intake.
If it's a 265, there will be no side engine mount provisions on the block.
 
#8 ·
The 55 and 56, 2 and single 4 barrel heads had ports that are extremely small; using ANY later intake manifold will result in an extreme mismatch between the intake manifold ports and the intake ports of the heads. The early 56 dual quad setup also used these heads with small ports. Mid year or so in 56, they switched to larger port dual quad intakes and larger port heads. You MUST use the 55-56 2 and single 4 barrel intake manifold gaskets with a latter intake or there may be a leak. Later intakes will work, but there will be an offset in performance due to the port mismatch; is it even worth it? I have two of the early 56 dual quad setups, and a single 4 barrel intake/carb (WCFB) to go with my #5603 casting number heads. I supposed you could use an adapter and a Quadrajet with a stock, single 4 barrel intake, or use an original WCFB ($$$), or even a Rochester 4 Jet. An adapter with a Holley is another option. Basically, you're very limited due to the small port heads you most likely have. Butch/junior stocker.
 
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