02 F350 buzz test and contribution test

[dragon71]

I have a 2002 F350 I'm looking at buying for a donor engine to put in my 2001 F250. The 02 truck has 181000 miles. The 02 is 2WD and the 01 is a 4WD. Should the oil pan and everything else be the same? I brought the truck to a shop and he suggested an injector buzz test and a cylinder contribution test before making the switch. The buzz test turned out good but he said the contribution test failed cylinder 8. The truck runs and starts great with very little blowby, (unlike the 01!). He said this was common on #8 and might have a weak injector. He gave me a bottle of injector cleaner (Penray) and told me to put a half tank of fuel through it and test it again next week. My 2001 had new injectors, glow plugs and valve cover wiring harnesses installed about 4000 miles ago so they will probably be switched anyway. He also thought when swapping the engine to also swap computers because the 2002 had a better one. Any other thoughts? Thanks!