4.2 internals into an 87 3.8L
Reply #22 –
Ok, so the externals of the 4.2L ARE THE SAME(Minus the intake) as the late model 3.8l, which I have in my car. the late model setup looks suspiciously similar to the 87 and up block, but only in pictures I've seen. Anything after 99(97 for the Windstar van) is going to have a split port intake. If you aren't swapping computers/wiring/everything, you have to either do the carb conversion like I did, or ditch the heads/intake off the late model 3.8L/4.2L engine. At that point you'll need port work to regain all the flow you've lost by using old style heads.
My '83 accessories would not bolt up, they had to be spaced out on the new style heads/block, but that was an '83 to an '03, things change a bit. I made them work, but swapped over to the later model front accessories(Alt, PS Pump). Eventually I'll convert the AC to work as well.
Hopefully that helps.