[Formulajones]

Originally Posted by scott70

Silversport recommended .68 with my combo even though they didn't ask much on driver styles.

Yeah, because honestly it doesn't come down to driver style. More importantly it's cruise rpm range based off your setup and intended purpose for the car. What ever drive style you have you adjust by picking a different gear to be in when you want to Then let the overdrive do it's job when you need it, whether that be highway cruising or road racing.

Madgoat is correct, the .81 overdrive was originally designed for road racing to have a close ratio from 4th with little rpm drop for long WOT straights. It was not meant as an overdrive ratio for the street originally.

The .72 which used to be the .68 option with TKO's, was meant for cars that have a tall rear gear like a 3.08 that people didn't want to change, and came with a 3.27 1st gear as a result to help takeoff with more gear multiplication.

When running 3.31/3.55/3.73 that .72 option isn't necessary and in many cases the 3.27 would be on the short side with those rear gears anyway.

You can look at it like this. Ideally you want an overdrive to provide you with a cruise rpm on the highway anywhere from 1800-2200 or 2300. That should range from 65 mph to 75 mph. Something in that realm. Any more rpm than that to reach those speeds and you start to lose the benefits of having an overdrive, which are using less fuel, less noise, less wear and tear, less engine temps, and just all around more comfy cruising. Based off your rear gear and tire size, play around with a calculator and see where you want to end up.

My small rant for the day, Tremec has already removed enough overdrive ratio anyway, that I wasn't a fan of to begin with. Instead of going to .68 they would have been better served to leave the .64 and instead change the 2nd and 3rd ratios for a closer ratio box. Because of those reasons I've actually become more of a fan of the G-force T5's. Rated at the same power levels but the ratios are more preferable. 2.95/1.94/1.34/1:1 and you have a choice of 5th being .60 or .63 and I think there is another one slightly more. What a sweet shifting trans that drives much like a close ratio muncie, and a 5th gear that actually does something, nice small light weight package that fits in anything, and surprisingly it's a few hundred bucks cheaper. 3.73's with this trans is perfect. I keep hoping Tremec will dive back into the gear ratios and offer some better choices.