From what I have seen the Y block seems to be one of the most cobbled togather motors after they leave the factory,I heard stories of them having many different years of parts including mismatched heads.  I went to look at a cheap 57 292 tonight for a set of heads for the 62 292 I will be building and it had a set of 60 heads which have the same sized valves as the 62 so I am still looking,along with the newer heads it had two styles of exhaust manifolds and a 56 on back 2 bbl intake.

Butchering up everything I can get my hands on in Dayton Ohio

My first core engine was a 292 which had been in a '57 F350.  It had one 113 head and a C head.  Someone had gone to the trouble of replacing the 113 intake valves to match the C.  At the time I thought that was terrible, but not now.   The engine no doubt performed its duty very well.  The amount of wear it sustained in cylinders and everything else before its junkyard trip was astounding. 

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.