That is discouraging. I've been in a similar situation with an Isuzu Trooper. I just wanted to take it to the junk yard after it kept breaking down (head gasket problems et al) The good news is, you have a great looking truck with a rebuilt transmission and brakes, what else could really go wrong other than regular maintenance? I'd probably go with the clearwater head and get that sucker running again, if you go with a used engine, not only are you going to have the labor to remove and replace, the replacement is gonna likely have issues too.

Now isn't the time to bring this up but that is why I held out and waited for the right V6 raider, less problems. (with the heads anyway)

Good Luck, it shant be long before you're ready to roll