The 4.2 is identical, but it's equip'd with knock sensors. That's the only difference in the block that I know of. Depending on the year of your car, you'e going to need a difference flywheel, oil pan, oil pick-up tube, and balancer. Also the pistons are different.
60' ~ 2.1, 1/8 ~ 9.61 @ 73.4mph
Living one day at a time!
DAMN Those are some old *** numbers!!! I need updated ones!!