Grabbed this engine core from the salvage yard today for that 4.0 rebuild I keep asking questions for. 400 with delivery, if it's cracked he said I can come pull another free. I know the mounting hardware to stick this into my 91 I'll have to use the old brackets. are there any other differences on the 4.0 if it's in a grand cherokee? The block is a 53020569 cast and the head is NOT an 0331 but I can't remember what it was. The coolant was clean green, the inside was only very minor surface dusting in the spots it had rust. I didn't spot anything in the oil or coolant, the water pump looked brand new so I'm jumpy, but I've seen no signs of headgasket failure.

2 questions, are there any common signs that an engine died to headgasket/overheating that might not be common knowledge? And second, when taking an engine off an automatic to put on a manual is there anything I could fuck up horribly? Thanks