70 dart 470 ci drag car build.

Wow, that is interesting and I'll pass this along to Tim because we've just been using 6 inch pipe, 12 foot long with 48 ×6 inch mufflers at the end with a slight bend from collectors to the ground which is about 2 feet
I'm not saying what you're doing is wrong I'm just presenting what Jere had to say about it.