Tranny question
Thread Starter
Heel & Toe
Joined: Feb 2011
Posts: 19
Likes: 0
From: Texas
Tranny question
Just bought a '69 from a fellow forum member, a great car with a truly bad a$$ engine in it. Most of the time I'll be driving it will be on quick country roads and the freeway. The issue I have is the same that I had with my '66, it needs another gear. (I swapped a 700R4 into the '66 and it's been perfect.)
The engine is a very cammy 383 stroker that revs like heck yet still has gobs of low end torque, (400+ hp and 400 lbs+ tq dyno'd at the rear wheels!) The car presently has 3.70 gears in it, (originally was 3.36), and an M20 or M21 4 spd (not sure which just yet). I presently show about 3200+/- rpms at 70 mph. Not cool.
My main question is: Can I save a bunch of dough and put something like a 3.08 rear gear in it and keep my present tranny, (which I like), hoping to see ??? as far as 70mph rpms go? Or, just bite the friggin bullet and drop the Keisler TKO 600 conversion in it?
Would the TKO and my present gearing make for a useless first gear though? As it is the bloody thing is through first in a flash.
Thanks in advance fellas.
The engine is a very cammy 383 stroker that revs like heck yet still has gobs of low end torque, (400+ hp and 400 lbs+ tq dyno'd at the rear wheels!) The car presently has 3.70 gears in it, (originally was 3.36), and an M20 or M21 4 spd (not sure which just yet). I presently show about 3200+/- rpms at 70 mph. Not cool.
My main question is: Can I save a bunch of dough and put something like a 3.08 rear gear in it and keep my present tranny, (which I like), hoping to see ??? as far as 70mph rpms go? Or, just bite the friggin bullet and drop the Keisler TKO 600 conversion in it?
Would the TKO and my present gearing make for a useless first gear though? As it is the bloody thing is through first in a flash.
Thanks in advance fellas.
Le Mans Master
Joined: Jan 2006
Posts: 6,506
Likes: 139
From: Butler Pa
It sounds like you have the M20 trans with the 2.52 first gear. The M21 has a 2.20 first.
I was in the same position as you. I have a zz502 and with the M20 and a 3.55 rear, it was through first in a flash. Not being ready to plunk down the cash for a TKO, I switched to a 3.08 rear and it made a noticeable difference. Enough that I'm going to stick with it for a while.
I was in the same position as you. I have a zz502 and with the M20 and a 3.55 rear, it was through first in a flash. Not being ready to plunk down the cash for a TKO, I switched to a 3.08 rear and it made a noticeable difference. Enough that I'm going to stick with it for a while.
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
I ran a TKO 500 with a 3.27 first gear with 3.70 gears in the rear. I had it behind a 450 HP SB for a couple of years. It was doable and you get used to it but first is pretty short. With the TKO 600s 2.87 first gear I would not hesitate to do it. I was actually looking to go to the 600 when I decided to put in a T56 with a 2.90 first gear. I find it very good and now have a 500+ HP SB in front of it. The TKO is a better option with a nice OD for highway cruising, but it is expensive. What isn't on these cars.
Thread Starter
Heel & Toe
Joined: Feb 2011
Posts: 19
Likes: 0
From: Texas
Thread Starter
Heel & Toe
Joined: Feb 2011
Posts: 19
Likes: 0
From: Texas
Had another suggestion thrown my way in lieu of a 5 speed swap, the Gear Vendors Overdrive. Got on their website and it looks interesting. I do like the thought of keeping my M20 however, the overdrive reduction just doesn't seem like all that much. It's .78 if I recall correctly and I believe the TKO600 was .67. Anyone have any experience with the GV unit? Thoughts and opinions appreciated.
Cheers
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