Many of you know I did one of the first conversions to a Tremec TKO600 in a 66/67 Chevelle. In fact we doccumented it here for all to use. One mistake I made and did not doccument the correction was that I used a .82 overdrive with 3.31:1 rear gears. This was a huge mistake. I wish they offered a .70 OD so the drop wouldn't be so huge but that's not to be so I am converting to a .64OD which is costly. The 3.31 is slugish out of the hole and it still runs 2400 RPM in OD. I just wanted to let everyone know the best possible combination is a 3.73:1 ring and pinion with a .64OD. That gives you 2000 RPM at 65. I had a bunch of discussions here while I was doing this so I thought everyone on this forum should get the word.

I will be changing the OD gears to .64 this Winter. Now I just need to find a good, used, 3.73 ring and pinion set...and come up with a bunch of cash to correct my error (haha). By the way, just for the record, Jeff Mortinson told me to go with the .64 and I disregarded his suggestion. This one was all me.

Chuck

Chuck, im running the .64 with my 3.31's and it's great, although i'd like the .68 (tko-500) ratio better, i cruise at 70 at 2000 rpm, and it's got decent response out of the hole, i ALMOST went with the .82 version also but im glad i didn't. Personly i think the 500 version is perfect gear wise for us, but it doesn't hold the torque :(

when i used a tko600, i ordered the .8 od, and ran 3:73 gears-with the cam/engine setup i had, running around in slower traffic, the car would buck like crazy, i kept having to push the clutch in and let it out again-i would use 4:11's and the .6 if i had to do it over again, or run a milder cam
i switched to a turbo 400, low first gear kit, manuel shift, had the converter matched to the cam, def running more rpm than b4, compared to running the tko in 4th gear, but like the way the car runs now

when i used a tko600, i ordered the .8 od, and ran 3:73 gears-with the cam/engine setup i had, running around in slower traffic, the car would buck like crazy, i kept having to push the clutch in and let it out again-i would use 4:11's and the .6 if i had to do it over again, or run a milder cam
i switched to a turbo 400, low first gear kit, manuel shift, had the converter matched to the cam, def running more rpm than b4, compared to running the tko in 4th gear, but like the way the car runs now

that's definately the cam, I "de-tuned" mine from a solid roller to a hydro roller, little less lift/dur. and now at 1500rpm NO bucking it SOOOO NICE!

I tried to get the .68 OD. It turns out it is the same shaft and gear set but it is lower because of the taller first gear in the TKO500. The .64 with a rear end change is the only option.
Chuck

when i used a tko600, i ordered the .8 od, and ran 3:73 gears-with the cam/engine setup i had, running around in slower traffic, the car would buck like crazy, ...
What was the engine/cam combo? At what speeds did you experience bucking? I planned to use the same OD and gear behind a 489 with a solid roller that should have about 600+ tq/650ish hp at 4500 and 6500 rpm respectively (think the trans will hold up at the track with drag radials or Hoosier QTP's? :) ). I figured that the motor wouldn't like the .64 under 70 or so. As far as using 4.11's with the 2.87 1st gear in the TKO, do you think 1st will be too short for a motor that has that much grunt? The car will see 75/25 street/strip duty.
Oh, and thanks guys for sharing your experiences with the TKO. Advice based on real world info is priceless when trying to get the combo right the first time.