Shoot for 9.5/1 or so...a cast crank in a bbc is good for 600 hp, maybe more. I would not bother studding the block either, but that's just me. If it gives you more piece of mind, go for it. I would sell those heads if it were me. If you're going to the track with it, they will not do for a higher rpm engine. They pull really nice, but run out of steam at 4.5K, and they dont flow that well even up to there. They were make for a truck, lots of torque and low rpm. The good large oval ports are (last three numbers) 781's, 049's, there are a couple others. Closed chamber heads (also oval ports) are 063's, 215's, 290's. There are also others. Most of the open chamber heads have a large chamber, mayabe 119 to 122cc. To get decent c/r, you have to use a dome piston. If you use the closed chamber heads, cc's are generally 97 to 107cc or so...you can use a small dome piston, or flat tops and mill the heads a bit. There is lots of good big block info in here, just do a search for combo's that guys are running. I will send you a PM or email with my combo...it's bigger, but the basic build will be very similar for what you want. 12's are almost impossible NOT to do with a mild big block. John