Originally Posted by YellowRose
...I have to take the car in tomorrow for an issue that sometimes it will blow smoke out the driver's exhaust after being driven, then sitting for awhile and then restarted...
Any thoughts about what this might be other than what he thinks it could be?..
Y-Blocks used 'umbrella-type' valve seals. They are notorious for every bad thing you can think of. They harden, crack, shrink, they don't hold on to the stem tower, etc. The umbrellas are totally useless after no time but hey, this was Ford's first attempt at building an overhead valve engine. Since then, engine engineering has made vast improvements because materials and the process of engine building evolved.
When I rebuilt my 'Y' I made many changes. My machine shop installed hardened exhaust valve seats, milled every mating surface, and machined my valve stem towers for Viton seals. This machining process allows the Viton seals' springs to hold on tight, and give better sealing forever. Modern engines and aftermarket heads (like Edelbrock) commonly use these seals, so they are plentiful and cheap.
for more details and pictures. The seals start at picture #23 and continue from #33, etc.
I hope this helps. Questions? - Dave