[427TJ]

Off the top of my head I think that LS-7 heads are the same as LS-6, etc., and are open-chamber. The main difference between the -6 and the -7 was compression and cam. The LS-7 had 12.5:1 compression and a wild, l-o-n-g duration cam.

My friend bought a crate LS-7 in 1988 to replace the 396 in his '67 Camaro SS 396. Holy ____, what a radical motor. The amount of overlap is such that the unburned gas that exits the tailpipes at idle would kill you in a matter of minutes. He let me take the car to a Super Chevy show back in '90 and while we were idling in the entry lanes the guy next to me said, "That thing's killing me." (I shut it off while we waited to get in.)

Another aspect about old vs. new BB heads is the exterior appearance. Old heads (no pun intended) have the water jacket plug in the front (and back) of the head, a casting line across the front, and the large-port versions have a small half-circle on top of the casting line so you know that it's a high-perf head. Oval-port heads don't have the half-circle.

Again, just going off the top of my head here guys, if I'm not exactly correct then feel free to clarify.

Another good book is "Chevrolet By The Numbers." Casting numbers, differences, etc., etc. Almost too much information to comprehend and that's why the book is so good.