If it is a Series 71 engine it should fit. Not sure there was any difference in the P/L between the BB and plain-bearing engines. I think right in that timeframe the Veco and K&B used the same parts?
They are decent engines if you get one that hasn't been abused or worn out. They aren't going to have the surface finish of a modern OS, etc. but for their era they were fine. And, it's old metallurgy. More oil, always some castor, be sure your tank setup is bulletproof and won't cause meltdowns,,,, All the usual stuff.
Dave