Not all THM350 or 400's for that matter had the same DRIVE gears. They were different. It also varied by year. In 1972, the BB, and BS 400 had a 16 tooth DRIVE gear. The BC, BT, and BU 400's(All big cars in 72) all had 18 tooth DRIVE gears. My 1967 BT switch pitch had a 17 tooth DRIVE gear.
That is a .785 adapter for a car with 3.64s. Non AC car. That adapter is unobtainable. Dont even bother searching for one. Doesn't exist. You can remove it and use the gray gear. With G60s you should be good to go.
Im talking about an original Stewart Warner. 785 adapter. New or used....good luck. I've been looking for 15 years
He doesn't need it. I put the gray gear in mine as per Dave Johnsons recommendation and it works like a charm. Within 3-4 mpg against my gps speedo on my phone
OK, that makes sense. Then the chart is too general regarding automatics to know what the driven gear should be, as it doesn't define automatics further than THM350 & THM400. Oh well. Thanks for the enlightenment. Appreciate the good feedback.
The chart would probably only be good for 1972 cars. I have, 1967, 1970, 71, 72, and 74 Chassis manuals. The 72 manual is the only one that shows the DRIVE gear tooth count.
Take that big nut off and it will look like this. This is out of a 4 spd muncie, 68GS 350. This gear has 20 teeth. The rear gear that was in the GS was a 390 ratio, which is the trailering option ratio. FYI, Not sure if this gear jives with the 390 & speedo as it was a parts car from original owner. He ran it at the strip.
