Just to help extract info......
.040 over flat tops are for the 429 crank or 460 ?
I think theres different pin height?
Got a piston part number ?

Stock cam .....which one ? 1973 ?
Got any specs?
New valves ......whats the part number or valve lenght?

I am no exspert like Paul Kane is ,....but from what I see in your post,flat tops /dove heads/stock cam......I would think the static compression "might "be a little high and the dynamic compression would be real high,which "could "cause heating issues.
I have no clue on the valve issue,thats why I asked for additional info for Paul or whoever may help.