I have 2 transmissions, both ZF 6's. One has a blue tag, one has a black tag. I seem to recall there is some difference in quality, gearing, etc., other than just the color of the ID tag. Any insight would be appreciated. I'm going to install one, and keep the second as a spare. Also, anybody know what max HP these transmissions are rated to handle?

Both are identical as far as ratios go
1st-2.68, 2nd-1.80, 3rd-1.29, 4th-1.0, 5th-0.75, 6th-0.50, Reverse-2.50
Black tag was made in Germany by ZF , has higher torque rating (450 ft/lb ) and is noisier .
The USA made blue tag unit changed the angle on the gears to reduce noise due to complaints about gear whine but in doing so lowered the torque rating (400 ft/lb )

I'm putting this in a 87 with a 395 engine for ITO class road racing. Sounds like the black tag unit is the one to install.

So noise won't be a problem :thumbsup3:
Are you running the original dual mass flywheel or a single mass unit ?

Found some ZF6 swap info

http://members.cisdi.com/~anesthes/zf6/
http://www.digitalcorvettes.com/forums/showpost.php?p=222921&postcount=2

True, noise won't be a problem. I've purchased a Fidanza light weight flywheel (aluminum) and a Stage 3 clutch. I was forewarned about the "noise" when eliminating the dual mass unit. But since this is not a street car, it just wasn't a concern. With radio buds, and ear plugs, I can't even hear the rev's to shift. I have to have a shift light.

Thanks for the links about the ZF transmission. Excellent info. Now I better check the clutch I have. Not sure if it takes the larger or smaller diameter throw out bearing. It looks like the clutch is going to dictate which of the 2 transmissions I use.