First off, welcome aboard, Jerry! You've come to the right place!
The logs show 4,650+- tt engine +airframe, 495 SMOH. I just went to look at the logs again and saw that there has never been an overhaul where the top and bottom have been done at the same time.
A legal overhaul requires a complete overhaul, not half and half. It cannot be 495 SMOH if you are correct and both ends were never done at the same time. It has never been "majored".
Last major done 1n 1992, 250 hrs flown through '96, a top done 4 or 500 hours b4 that.
What you're describing is a bottom overhaul in 1992, and a top overhaul before that, but they cannot be combined and called a major overhaul. It sounds like there is no more than around 900 - 1,000 hours since any part of the engine was looked at, but it's still not technically (or legally) a major overhaul by FAA definition and regulation. From the information you've provided, I'd say this engine has the equivalent of 4,650 hrs +/- TSOH. With about 900 - 1,000 hrs since top overhaul, it may be past time for cylinder replacement.
NOTE: If the cylinders were
overhauled and reinstalled when the bottom end was overhauled, then it can be called a major, if all other overhaul requirements were met, but this is not what you've described.
With 495 hrs since bottom overhaul, It
may be as good as or even better than a 1,000 TSOH engine, but that's a very big unknown value! Without a complete overhaul at any given time, a lot of shortcuts could have been taken, and probably were, since funding was apparently a big factor in the decision making.
None of the great paint, great avionics, horton stol, alternater, nice int, complete logs, IFR etc. is any good, if the engine isn't reliable. It's just too big of an unknown quantity to know if it's a reliable engine or not. The price of this plane should (I think) reflect the possible need for a major overhaul!
Remember, we are all going to play devil's advocate and try to keep you out of trouble here. It may be prove to be a wonderful plane for you, but you need to realize the possible pitfalls before purchasing anything.
