I bought my 4.2L short block used out of a wrecked F150. It was built low compression for a single turbo appliction. I slapped my loaded heads and ported mustang intakes on it at first. The main thing was upgrading to the 01 oil pan. The 99-00 panis slightly different and doesn't allow the crank to fit. Best part was looked stock on the outside. I put down over 400 on spray. Switched to the M112 set up and never looked at nitrous again.

 

So if I were to get my hands on a 4.2L short block, it'd be a driect bolt-in swap? Do you know what the 4.2's numbers are, as far as piston dish, compression chamber of the heads, bore/stroke, etc?