Alright I need a little help. I am getting ready to start fabricating an exhaust for my 29 model A sedan. It has a 350 sbc with lakes headers. My question is, what diameter exhaust pipe should I use? I have seen some charts that recommend a 2 1/2" dia. based on this engine size (c.i.). The lakes headers have a 2 1/2" outlet flange. I want to use Smithy mufflers which have 2" inlet/outlets. I can come out of the headers with 2 1/2" and reduce down to 2" under the frame, but I am curious if this will have any noticable effect on performance.
Yes, the 2 1/2 before the muffler will be useless. I would try to stay at 2 1/2 all the way or 2 1/4 minimum, if the motor is mild. if you run 2 1/4 you can probably get the mufflers opened up to that size, 2 1/2 might be too much to get the inlet and outlet blown up too. Check with your local exhaust shop to see if they can help you.
Thanks. I understood that reducing down would be the same as basically running 2" pipes. I was curious if others using Smithys are running 2" pipes and if they felt some performance was sacrificed to get that sound.
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