I am going through the exact same thing right now - budget rebuild and I just want to make some compression. My '77 440 had been recently rebuilt and is .040 over - and the pistons were way down in the holes. I had .050 shaved off the block deck and hope to use a set of closed chamber large valve heads. I did the math and it works out to 9:1. The crappy thing is with this low compression you cant go too big on the cam (big cam = more overlap and duration) because it will kill the compression even more.
I will probably do a proper rebuild a year or two down the road and stroke it at that time - as long as my taking .050 off the deck hasn't limited my possibilities.
