Re: 86 to 90's 2.3L swap
yes you will be able to use the short block,, is your 86 EFI or carb?
you will have to swap some parts over from the 86 to the 90's short block,
you have a 4 plug head, so you will want to swap that over, also if you are carb, look at where the fuel pump mounts on the 90's short block, it may be cast or may have a cover plate, if it is cast over, you will A) have to grind out the the FP hole OR B) buy a 7psi eletric fuel pump
being an 86 engine, I would start off by pulling the VC and inspect your cam, you have a slider cam from the factory, and they do wear bad, and will cause the truck to run sluggish, you may be able to swap in the later model roller cam ($50-$100 off ebay) and solve your prob....
you can also build the 86 for less if you short cut the build, do an overhaul.. a backyard build if you like... just get rings, bearings, and gaskets, maybe $300.. yes you may still have some blowby if you have excessive wear in the cylinders....
the best thing to do is what is the budget you have in mind ? is the truck EFI or carb? but from the sound of it, its going to be $300-$500 no matter how you go