I have a1985 c7000 single axle with unfortunately has the notorious 8.2l Detroit in it and of course head gasket issue
I want replace the whole thing and wondering what would be the best replacement need more power. thanks
Ward.

 

I would go with a mechanical L6 turbodiesel.... pick your size and a trans from a similar class medium duty truck. Cummins or International would be my first picks. May even consider a Ford 6.6/7.8L if the price was right.