I had 3.08's in my 83 and my car ran 12.6 @ 110, I put a set of 3.73's in, and ran 12.3 @ 115 mph. 4.10's put me at 12.0 @ 115. This might be irrelevant because I'm running a c4, but I can tell you this, you won't be disappointed.
IT LIVES!!!! I thought I blew my engine at the MOMS race on Sunday, but it turns out that I kicked a exhaust rocker off. I've had that happen before, but it sounded a lot different, and never with the poly locks.