Searching the internet, I find that 454 Magnum block and heads are different than the 7.4 litre.
I currently have a tired 1988 7.4 litre and my mechanic says the best way to freshen the engine is to buy a 7.4 litre long block and replace it with the present engine. Which is in a '88 Formula F223 LS.

I ask him if I can replace the current engine with a 454 magnum block. He is not sure. The only difference he sees is the oil cooler is on a 454 magnum and not the 7.4 litre.

Does anyone know what else is different between a 454 ans a 7.4 litre?