[ChevyBelly]

First off, I have a 350 block with 305 heads. Is this a standard 305? Maybe the engine was rebuilt this way. The block code is CMA with the 1974 code date. ( CMA has a 1972 date also )

But anyways, I bought a set of Summit headers http://store.summitracing.com/partd...4294923429+400304+4294839039+115&autoview=sku And I want to reuse the stock exhaust system with the Y pipe and reducers to mate up to the 3 " collectors. Is this doable or a bad idea? I just want this to last the summer. I eventually want dual exhaust but for a 454. If I get the dual exhaust system now with 2.5 or 3" pipe, would it hurt engine performance with my current 305 engine?

engine has rochester 2G ( 500 cfm ), TH350, and stock 2.73 open rear

 

[63 Chevy II]

Go ahead. 2.5" or 3 is fine for a Small block. I say run the duals now.

 

[slow3oh]

you can use the stock exhaust but don't expect to see any hp/tq gains if thats what your looking to do.

 

[ChevyBelly]

Should I run 2.5 or 3"? The new engine will be a 454 bored 0.030 over with no more than 500hp.

 

[slow3oh]

Should I run 2.5 or 3"? The new engine will be a 454 bored 0.030 over with no more than 500hp.

2.5 is good to about 450 horse so i am sure it would be fine with 2.5 but if you want to be safe the 3 inch would also be perfect

 

[luepke75]

duel with 3" gets my vote if you are going to have the new motor. Should be fine with either motor.

 

[novaboy009]

I'd do the dual 2.5". 3" gets noticably louder and is tough to fit under the car (clearance issues with the ground and rear axle). It will bolt right up to your big block when the time comes.

Kev