My brother has a 90 ram with the v6 and automatic in it. He picked up a 78 318 jasper motor and would like to install it. The guy that sold it to him fed him a line and said that all he needs to do is get a 90 distributor and put the motor in and that's all she wrote. Believe it or not the guy also told him that even though the 318 has a carburetor he could just hook the fuel line to it and it would be fine.

I am trying to convince him to just rebuild the 3.9 the truck afterall has 220,000 miles on the tranny and rear end

Can you guys shed any light on what might be involved in replacing the V6 with the V8

Thanks for your help

 

Your brother will need:
flywheel/torque converter with zero balance (read: not for a 360)
motor mounts, maybe cross member too
maybe bigger radiator
maybe different tranny/bellhousing
different fuel sender without the in-tank pump
and there might be other stuff too - ECM, etc.

And if it's a 318 out of a van it'll have the wrong oil pan.