The 258 is a better choice - it is lighter - the car handles better - it bolts in without having to change the entire front crossmember and springs and trans and rear . The trans won't take the gaff from a V8. Neither will the driveshaft u-joints nor will the rear for very long. And you'll need big disc brakes. You can swap in a 1990 258 and scrounge up a Ford SVO Turb for about $125.00 extra - swap in a RENIX fuel injection rig from any '87-'89 AMC 4.0 - find a cheap intercooler from some Jap ride ina junkyard online - voila - 300HP. Way to go dude. Car will handle better without the weight of a snowplow out there. I've an '81 Eagle Kammback - in reality it is a Gremlin 4 x 4 - . This is the way . brien