Full Size Jeep Network

I’m preparing to replace a Flexplate, 1980 J20 360/727
I’ve heard of potential conflict with heater box and exhaust manifold
Should I leave the manifold on the pipe (more rusty bolts) or just undo the pipe?
I’ve pulled engines on fords and chevys , but not Jeeps
Any input would be greatly appreciated

Id at least try to see if the bolts losen and come out on the manifolds. My 90 i waited years.. using puddy on exhaust leaks on the head lol.. only ti grow a pair and find out all the bolts were easily removed and i could put in new gaskets.

Maybe youll be lucky like me