QUOTE:
A.) My car is a 1990 350SDL, My goal is to replace the 3.5 liter short block (244,000 miles still runs fine) with the heaver/stronger built 3.0 liter short block (187,000 miles). I want to build the 3.0 short block to go another 150,000+ miles.
Help me understand something about your car. You say at 244,000 miles the 3.5 liter still runs fine. So, why do you want to change it now? I understand about swapping to a 3.0 liter, but I would not want to be without my SDL while the work was being done ......I'd wait until the 3.5 liter was NOT running fine.
Is your 350SDL bored with the 3.5 liter and wants to become a 300SDL?