:head:how fast do you expect to go with 4.3 v6 you are really flying with the 3.7 good luck with your new power plant

I'm with Ferm, I'd rebuild your 3.7 or find another. My buddy and I both rebuilt out 170's for around 700 -1500 bucks, complete! Mine was already bored to .040 over so I replaced the rings, two pistons, bearings, gaskets, pertronics ignition and new head for around 800.00 dollars. My buddy's was original, had his bored .030 over, new pistons, rings, bearings, gaskets, oil pump, and head for about 1500.00 dollars. We both are mechanics so we tore down and reassembled both ourselves. They're very easy to rebuild. Both are running very strong with no problems. Find a good machine shop and do the numbers, you might be surprised. Its something you should consider.