Hi Joel,
Engine numbers can sometimes be deceiving. If it is a late model engine such as from a Camaro there might be several identifying factors. First of all, does it have the mounting bold holes in the heads for the alternator and power steering mounts? If not, chances are that it is an earlier model engine, possibly original the one from the truck.
Does it have side motor mounts or are they on the lower front of the engine? The later model engine has places for the older mounts but the older ones do not have the holes for the later style motor mounts. You can look on the side of the block below the exhaust manifolds... if you see a set of 3 holes in a triangular shape, it is a later model engine.
If this be the case, look behind the drivers side head between the transmission mounting surface and the head. If it is out of a Camaro you will find the engine size designation in raised numbers and letters, ie. 305 being 5.0L, 350 will have 5.7L. Now, depending on what year it might possibly have came from should it be a Camaro, it could have been a lot of things. The early model Camaro had the valve cover bolts on the outside of the cover, the later model (possibly 86-on) Camaro would have the valve cover bolts in the center of the valve cover.
Even at this, there is no guarantee that what I am saying above is correct, other than the engine size in raised letters behind the drivers-side head. I say this because on a Small block Chevrolet, just about anything will fit anything with very few exceptions until you get up into the mid 2000 model years.
Unlike Ford, where hardly nothing will fit anything else, Chevrolet, up the model years 1986-on, pretty much everything will interchange. Even after that, most items will still interchange up the mid 2000 years. For instance, a flywheel from a 235 six cylinder engine will fit a 427 V-8. Starters will interchange depending on whether it is a straight bolt pattern or or offset. All cylinder heads will bolt on from one to another, and all intakes up to 1986.
There is a lot I don't know about your particular application so If you could narrow it down from what I have mentioned we can investigate further.
Ed
