installing o/r h-pipe

stprorolla49 said:

yea....i tried to tell him the same thing...i was gonna special order some stainless grade 8 bolts from an industrial supply company about 20 min from us, but he said that when we were takin the stock h-pipe out, there wasn't really enough clearence to get a bolt through the hole in the header......also, what size bolts did u guys buy...if i were to buy some bolts, i wanna make sure i get the rite ones.....as of now, i think that they are 2.5 in x 11mm????????

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Here is how I figured mine out. The width of the bolts needs to be thinner then the inside of the threads on the studs.

Since the studs screw into the header flange, and sit flush with the top of the header flange, your new bolts need to be long enough to go through the header flange, into the new h-pipe flange, and still have enough threads to put a nut onto it. So length wise, you need the bolt to be about 1/2 inch longer than the ENTIRE length of the stud, including both top & bottom threads, and nut in the middle. So just measure from end to end, know what I mean?

Or, you can get new studs from Merle's. That is where I got mine, and that way you don't have to put a wrench on the top of the header flange to tighten the nut on the bottom. The stud is a 12mm w/ 1.75 pitch threads. I know that because I used thread chasers on all of them to make them easier to install.
Scott