JayEstes 173 Report post Posted June 11, 2023 12 hours ago, Mach1 Driver said: Jay, do you have the stock 2-1/4 dual exhaust with the resonators up front and the transverse muffler positioned on edge between the pumpkin and the fuel tank? I've often wondered how close that gets to the sender wire, but it makes sense that there would be less exposure to the muffler coming out the center than running across the tank from the side. Well, sure enough, I had my harness routed improperly. I never knew about that routing hole in the left side pocket- but it’s in the exact right place. So I fixed it thanks to everyone. And No, that reverse light harness is never near either exhaust line line I mentioned. Per the dual exhaust- I never knew there was a transverse muffler option. I pulled the original crappy exhaust manifolds and single line I had and put cast iron headers with 2 separate 2.25 exhaust lines on each side with h-pipe. thanks Mike for asking the question- I’m getting more out of this than I put in! Jay 1 Mach1 Driver reacted to this Quote Share this post Link to post Share on other sites
stangs-R-me 124 Report post Posted June 11, 2023 We are getting a bit off track as far as the thread "subject" goes but ... The only way factory dual exhaust came on '67-69 Mustangs & Shelbys was with the dual resonators and the transverse muffler. It was the same system dimensionally for all 3 years but there are two different systems: 2" for 289, 302, 351W & 390 2-1/4" for 428, Boss 302, & Boss 429 Interestingly, the small block H-Pipes are all 2-1/4" and will bolt right up to the 2-1/4" system which is what I have behind my 351W. Why the 390 Big Block got the small 2" system is a mystery. In 1970, all Mustangs with dual exhaust went to the more common and simpler dual muffler set up in front of the axle and all were 2-1/4". If you have a '67-69 and want the more normal dual muffler set up, then you just order 1970 exhaust and obviously there is no issue with the center exit fuel sender wiring. Doug Quote Share this post Link to post Share on other sites
Mach1 Driver 596 Report post Posted June 11, 2023 2 hours ago, stangs-R-me said: We are getting a bit off track as far as the thread "subject" goes but ... The only way factory dual exhaust came on '67-69 Mustangs & Shelbys was with the dual resonators and the transverse muffler. It was the same system dimensionally for all 3 years but there are two different systems: 2" for 289, 302, 351W & 390 2-1/4" for 428, Boss 302, & Boss 429 Interestingly, the small block H-Pipes are all 2-1/4" and will bolt right up to the 2-1/4" system which is what I have behind my 351W. Why the 390 Big Block got the small 2" system is a mystery. In 1970, all Mustangs with dual exhaust went to the more common and simpler dual muffler set up in front of the axle and all were 2-1/4". If you have a '67-69 and want the more normal dual muffler set up, then you just order 1970 exhaust and obviously there is no issue with the center exit fuel sender wiring. Doug You are correct, we are getting off track, and maybe I should start another thread. Thanks for the info, I wasn't aware that the 70 had dual mufflers in front of the axle as well as transverse. I have both 69 and 70 Part and Body Illustration Manuals and they do show this with part numbers, but I could find no on line reference to the DOZZ-5230-E&F, D&B, J&C, OR G&H mufflers so it isn't possible to find pipe and muffler size. I think the challenge in using a 70 system is finding one that is close to authentic. Everyone that makes a muffler has a system and they are all too loud. At least the transverse system is reproduced and has a period correct tone that isn't so loud that it will drive you nuts. Quote Share this post Link to post Share on other sites
stangs-R-me 124 Report post Posted June 11, 2023 NPD shows the '70 System: 5210-29: use with turn downs 5210-27A: use with Mach 1 Tips There is also the concours correct option, but you need to buy all the pieces separate. Doug 1 Mach1 Driver reacted to this Quote Share this post Link to post Share on other sites