Block out of square

PRH said
I don’t have easy access to a SB block, but I checked a BB....... it’s about 8.5” from the crank c/l to the top of the bell housing flange.

If that were off .046”, it would be about .32*, which works out to .067 in/ft, so for the length of the crack would be in the .122” neighborhood.
Still so far off nothing would fit right.

You’d really have to work at it to screw up the line bore that much.

And then there’s still no timing set that would fit.

I still believe the actual “issue” is the way the back of the block is machined, relative to the decks, main bore, cam bores.

And I think it’s always been that way.

Just get another block and start over.

To make things worse if the crank is not perpendicular to the rear face of the block you'll have the clutch assemble (which is bolted to the flywheel) rotating on a different plane than disc, which is connected to the trans input shaft. In theory the disc will make contact with the top front of the clutch and bottom rear before anywhere else. I'm not sure how this would effect the smoothness or lifespan of the clutch?? Treblig