Hi Clois,
Yes a 390 with a 428 crank is 410ci. (Don't know about NASCAR racing though)
I guess it all comes down to cost. I was planning on putting in a new cam with some roller tipped rockers and have some porting and polishing done.
I suppose when it comes down to it, that would be a better way of improving the engine instead of getting 'fixated' on it not being a 428.
+60 on a 4.13 bore (4.19) is quite a lot. I'm not suprised it may have gave problems. +60 on a 390 should be a lot more reliable since there should still be quite a lot of wall left. Actually, I'm just thinking, the numbers I was given was, it is currently 4.0866 and they want to take it to 4.10, thats a +50 surely! +60 would be 4.11
Oh well, im sure it will all make sense eventually
Paul