[STEELCITYFIREBIRD]

FWIW, I am putting together a 400, same exact block,75 on valley... Original block that came in my 76 formula. I have an earlier 1970 block that I am saving for a long stoke motor.
At the (dirt) racetracks they use a cube checker in the limited classes, measures amount of air displaced by sweep of one piston. Not sure if anyone else does that.

Someone probably has a good reliable way to measure the stroke assembled, that may chime in. I've never done it, but I am sure it can be done.
Pulling the right plug may allow you to see in a cylinder to see if it has dished or flat top pistons in it, that might be very telling.
I'd have to know weather me and him need to have a chat.
The block isn't a reason to have a "chat", the rotating assembly would be.
Don't despair over the block, just try to verify what is inside so your not chasing your ass tuning it.

She is a nice ride, just don't hammer her too hard!
No 4g holeshots!