Question about an Engine

I have a 1991 Z28 Camaro engine that has 170,xxx miles on it and I just recently found a 1988 305 IROC engine that will most likely fit in my car and has been machined and has less then 1,000 miles on it. The '88 engine was rebuilt. Block was machined along with heads, MSD distributor, A/C, wiring, a complete engine. The thing is, the guy told me the engine has been sitting for a few years now.

What could be wrong with the engine since it's been sitting for a while? The engine does have oil in it. I was told by my mechanic to try to turn the crankshaft and see if the engine turns over. If it doesn't, that means the o-rings are fried from condensation and could cause misfirings. Is this true? If it makes any difference, the engine was kept in his garage for the years it was out of the car.

The main thing i'd like to know is what could be wrong with the engine since it's been sitting for a few years, and what can I do to make sure the engine runs? Like lift the valve covers off or something?

The guy has receipts from the machine shop as well.

The bad things about an engine sitting idle for long periods of time involve seals drying out and becoming brittle increasing the likelihood of oil leaks . . Even though the engine contains oil , that doesn't necessarily mean it has been protected ! Over a period of time , the majority of the oil drains down into the oil pan and the upper engine parts are exposed to moisture and can rust . This is especially true with the pistons as pistons and cylinder walls can rust . A lot depends of how the engine was prepared for storage , if it was prepared at all ? There is no way to see if the engine runs unless you have an engine run stand . I have seen people sit the engine securely on the ground , hook a battery up to provide power to start the engine and pour small amounts of gas into the carburetor to start the engine . This can be VERY DANGEROUS and I would NEVER suggest doing it that way ! If the engine is fuel injected , well ... that adds another degree of difficulty to the equation ! When you buy an engine that you can't personally see run beforehand , you are taking a chance on the engine being what it is represented to be . You are also taking a chance on the seller's honesty about the condition of said engine ? Just my $0.02 - take it for what it's worth !

If the engine was properly prepped for storage, as Old Blue says, then it may have a chance. This involves pulling the sparkplugs, fogging the cylinders with oil, (after draining the old dirty oil out, filling with clean oil and running it), removing the rocker arms to allow all the valve springs to extend, then protecting it from moisture and dust with a large engine bag, (after ensuring ALL coolant is drained and the water jacket is bone-dry), etc. And preferably turning the crankshaft every few months. Even then, you are taking chances, especially if it was in Florida with high humidity. And considering that some of those valve springs have likely spent YEARS in the fully-compressed position, I don't think I would go that route, unless it was DIRT cheap, and I could afford to make the mistake if it is not what it's claimed to be. (For starters, I would ask a LOT of questions, such as: Why was it pulled with less than 1K miles? How was it prepped for storage?). Pull the dipstick out, and see what's on it. If there is oil on it, and it isn't crystal-clear, walk away. Used oil is acidic, and will etch cylnder walls and bearings, even while sitting. Pull the oil-fill cap, and see if the underside of it has ANY residue on it. (Moisture, sludge, anything that leaves a dark smudge on your finger). Again, if yes - leave it for someone else. You need to be willing to spend the $ to rebuild it all over again, or take the $$ hit and unload it, if it isn't perfect.

Another question for you: Is the engine in your 91 Camaro a 5.7/350? Is it worn out/smoking/knocking, etc? I ask, because a perfectly rebuilt 305 will still have less power than most worn 350's, even with 170K miles. The 305 was not a good engine from a performance standpoint. You'd really be better off rebuilding your 350. Or getting an exchange long-block, (basically a completely rebuilt motor, except you use your own intake manifold, oil pan, etc). They are cheap and plentiful, and many have a 50,000 mile warranty.