Exhaust, choosing the right diameter?

[SandDiesel]

I have a very small and cheesy exhaust under this car I recently purchased (65 Belvedere). It has a 383 with 1 3/4" headers and a 4 speed behind it. I intend to build a mild 383/400 stroker for it at some point. Should I go 2 1/2 all the way out or can I go 3" pipe and mufflers to 2 1/2" tail pipes? I am guessing the headers will be replaced with 1 7/8" or more. Trying to avoid paying for two systems. Thanks.

 

[Meep-Meep]

1 7/8" headers should be fine with the 1.74" valve and I'd run 2.5" pipes all the way out. My setup with a 440 (1.81" valves) has 2" primary tubes with 3" pipes all the way out.

 

[SandDiesel]

If I decide to build a stroked 383 or 400 will 2 1/2" still be sufficient? I know bigger isn't always better but I'd rather give up a back pressure now than replace the pipes later. I hadn't thought of exhaust valve size as a factor, just thinking cubes. Appreciate the info.

 

[Cranky]

RPM is a factor too but I also think 2.5 is plenty. 3" is for the really radical setups.

 

[SandDiesel]

Thanks Gents.