Antarctico

I need to replace the whole system -- my mainfold is cracked in the usual place these things brake, my catalytic converter is shot, and the muffler has a hole in it big enough to put three fingers through. What I am shooting for is the header, a Random Technology high-flow cat, and a Flowmaster 50 Delta Flow (for the nice sound). I know it's kind of silly to be spending any sort of money on a old truck like mine, but hey, it's my truck. :)

I called Borla and talked to a fellow named David. He says because the header was built for a truck with a manual trans, and because the automatic is a bigger unit than the manual, this is why it won't fit. I think this sounds a bit like BS to me, I doubt he had anymore familiarity with the header than spec sheet he had in front of him, but I've never had the chance to compare the dimensions of the manual vs. automatic. The header uses its own crossover pipe, so maybe this is where there is an issue. Borla has a header for the '91 Comanche/Cherokee that works with either transmission, but it does not have an EGR port like the header for the older motors. Unfortunately, I live in a state that uses a dyno for its emissions test, and that means having to worry about stuff like this if you want to pass.

Ah, now that makes some sense. Is the interference from the header itself or the crossover pipe that goes across the top of the trans?

My Comanche is an '89 4.0L RWD automatic with the six-foot bed. It's finally time to replace the exhaust system of my truck, and I've been wanting to replace the cracked stock manifold with a header for a while. Any suggestions? Borla offers a header for my year and model (Borla p/n 17010), but they only spec it for a manual transmission truck. Anyone familer enough with this header to be able to tell me if it might fit a truck with an automatic, or if not why? Thanks! :)