I'm trying to fix an exhaust leak on my HP manifolds.I checked by hand and the leak is at the flange even with 2 gaskets. The exhaust guy used some crap flanges to begin with , then I went from 383 to 440 and had to tweek the pipes to fit. Now I want to start over with new flanges and start with 3" pipe and go all the way back, I currently have 2 1/2" with 2" tail pipes. Weres a good vender to find these parts at? Maybe they are a stock item at an exhaust shop. I want a hole to hole fit with no slotted holes or sloppy fit though.Thanks