327/300 carb CFM
 

Anybody know the CFM rating on that (AFB) carb ?

Re: 327/300 carb CFM
 

Mark, I am 99% sure it is 575 CFM....I was planning on putting a 300 HP in this Nova for SS/IA when finances (and too many cars) got in my way....LOL

Re: 327/300 carb CFM
 

Mark,

I was never sure of the rated CFM but it never seemed to be able to produce the extra 50 horsepower on the 327 that the General assigned it. On the other hand, if the 300 horsepower manifold had never been cast, where would the 283 cars have ever found that last 50?

c

Re: 327/300 carb CFM
 

Something else that should be "fixed".

Re: 327/300 carb CFM
 

Thanks...So it's 15 hp in a 65 Chevelle as of now ... roughly 180 lbs in J/SA over a 4GC..
I don't see it carrying that difference...Of course, without a dyno sheet.....???

Re: 327/300 carb CFM
 

Yes, I believe it IS 575 CFM. EXACTLY the same measurements as the dual 4 barrel carbs on a 409.

Re: 327/300 carb CFM
 

That carb wasn't the only difference between the 62-65 250 and 300 horse 327. A good question was brought up, but I'd like to know what the CFM rating of the 4 Jet carb that the 220 and 250 horse small blocks was. The intake difference was notable, and the 461 head as opposed to the 520 head was another factor. Is the factored horsepower really that great a difference?

Re: 327/300 carb CFM
 

and to that, Greg, part of the horsepower difference was in the upgrade to the 2 1/2" outlet exhaust manifolds on the 300 + up horsepower engines.. With headers on the engines, the performance difference was not as dramatic.
I believe the little 4GC ( 4 jet ) was around 450-475.

Re: 327/300 carb CFM
 

520 heads on 327 /250's was 64 and earlier.
65 327...Same exact specs except for carb.
My question has to do with how much real dyno hp and whether the AFB is worth the hp to offset the weight.

I had a friend who bought a 65 Impala, 4 speed ,327/250 new, and it came with single exhaust .
I doubt you would have seen a 327/300 that way...Ancient history though.
We're living in the Now !

Re: 327/300 carb CFM
 

Seems to me a 62-64 327 300 used the same 2 1/2' exhaust head pipe as the 409 340,380 and 409 horse engine. I didn't consider that because,like you said, discarding the stock exhaust for a pair of headers negated any differences in the OEM exhausts. The NHRA factored horsepower was 250 horse for the 62-64 327/250, and 265 for the 62-65 327 300 horse engine. Someone should give it a try! Imagine a 327 265 in a Nova.Might be fun, especially with a 3 speed automatic.Interestingly enough,the 65 250 horse had either a WCFB or a 4 jet with 461 heads. Horsepower rating was the same as the earlier engine with the 520's.