So Just curios how much Hp loss do you think I could get from a TT Autronic EFI deal from changing exhaust??? 519 ci Dart pro 1 325cc heads 14 psi boost no big deal cam +/- 630 lift full roller. (Meaning from open shorty dumps to threw transom) Water exit's at the end of the tails double walled +/- 2 in from exhaust stream with threw transom exhaust as opposed to no water at all with the shorty dumps?? pics to follow. Shortys are 3 in i.d and threw transom i.d are 3 in stepped to 3-1/2 to 4 to 4-1/2 i.d. First pic shortys, second pic threw transom, (and I have already taken out the mufflers due to thinking restriction) And I've already spoke to some very knowledgeable guys so please don't call your guy to elaborate as I am not looking for their opinions, Im just looking for you guys that have knowledge on this site about these things before I have a guy come out and perform the tune. And I'm just blown away on how much change that I have noticed. Thanks.