replaced the oil pan gasket on my 91 and holy crap was it a PITA. i took the exhaust manifold off, cut the old downpipe off since i had a new one to put in anyway, and cut the cat out since someone JB welded it to the down pipe. the biggest hangup i had was getting that transmission inspection plate back in between the oil pan and the transmission. after like an hour of taking it down and putting it back up, i finally got it together. i dont know if theres a trick to this or what. but good luck to anyone else doing it.