It would be easy enough to verify TDC , time it, put some race fuel in it and see how it runs. Not much to loose and if it runs good have it whistled. If the compression is too high then maybe a compression adjustment is all thats needed. If the compression ratio is acceptable and you're really lucky maybe all it needed was timed correctly. Worse case is it still runs bad and you learned some new skills. Then you can tear it down and start over. On the other hand if tearing it down is what you want to do anyway and your tired of screwing around with it I can relate to that. Have at it.