i have a stock 1989 lsc. i has a cat back dyno max exhaust system on it when i bought it. Could i just buy an off road H pipe for a mustang and will it fit without much modifying? -thanks-

I don't think it'll fit (different chassis types). But looking past this, why remove the cat system? If your cats aren't plugged and you're just looking for a big pipe system you might consider a trip to the muffler shop for high flow cats. But be careful, depending on your engine mods you may rely on your current system more than you think. Some backpressure is good, assuming the car in question is street driven. Either way if you make any changes you'll be up on a rack at the muffler shop to do it, if they'll remove a federally regulated emission device. Ohh, now I see. That's why you want a bolt on pipe. Hmm, better keep em'. Think green:D

The H-pipe should bolt right up, it is the intermediate pipes and tails that need to be lengthened. I agree with above, though; no need to ditch the cats or do anything to the exhaust really unless you do the whole thing to at least 2¼".