When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
According to the books I have, the 76 standard ratio first gear is 2.64:1 and the close ratio is 2.43:1. So, if you have it disconnected from the engine or out, put it in first, mark the input shaft, and spin the tailshaft. If you get less than 2.5 revolutions, it's a close ratio, if you get more it's a standard ratio.
Two grooves is the 2.43 gear ratio set; 3 grooves is the 2.64 set. For a good source of information, go to the following: http://pontiacpower.org/BW.htm
larrywalk, thank you sooooo much for posting that link. I had it saved on an old computer that crashed and have done a ton of searches trying to find it.
I have one with 4 grooves but I can't see any dimples in the gears that would indicate it is a nickel geared piece. I'm hoping it is, looks like I may be selling it in favor of a TKO-600.