Why is it that my 427 goes from 2 1/2 inch down to 2 inch from the manifolds?

Why wouldn't they, (Chev), open the whole thing up and make it 2 1/2 inch all the way to the back? Heck...it's a big block!

 

Also, I have new front and intermediate pipes coming from Corvette Central. Looks like the originals were clamped. Should I use clamps or is it ok to weld them and still be okay with the NCRS folks?

 

Thanks

Kev

If you plan on doing NCRS Judging, it's best to use the same type of fastening as original. Without looking at the AIM, I couldn't say which way yours was originally, but it's safe to say that the head/intermediate pipes were most likely clamped. Some years had mufflers welded to the rear pipes, some were clamped....same with the exhaust extensions/outlets....some welded, some clamped.