5.0 questions

I have 4 parts cars, mustang and capri 5.0 HO motors 5 and 4 speds 83 84 84 85,,,How strong are the 4 speeds in the 84 All have holly 4 barrels one used spark plugs listed for explorers the mustang ones didn;t fit one looses oil pressure when it gets warmed up. I rebult a motor for my ranger mini truck and used a mustand pan and pick up tube and it was almost totally plugged with sludge is this a common problem with the long mustang tube, I have a 29 roadster the 302 is tired;
glass 32 body, 31 chevy cut down coupe and 1919 durant touring body,, lots of projects to build maybe one wil get a chevy motor