The fuel tank mounts the same as a 68, but you are right. There is not much real estate back there so the location of the cut outs is pretty important. If you are interested I can make a set of templates for each side located off the frame rail. Which is what the tips mount to. I have an original 68 340 car to make templates of.
Thanks Furrystump, thats mighty kind of you! Since I already have my exhaust I think for now I will go in the direction I am going. Like you said now would be the time and it would look so much cooler but for now it will stay original,
