drwet

Its almost time to start my manual trans conversion. I am trying to decide which transmission to buy. The TKO 500 I am leaning toward has a first gear ratio of 3.27:1. Combined with my 3.55 rear gears it gives me an overall ratio of 11.6:1. Is this about right? My '66 has a close ratio trans for an overall ratio of 8.14:1. This is too tall for a daily driver. My buddy has a small block S-10 with a T-5 that has a first gear ratio of over 14:1. That's too deep. I would like to hear from C-3 owners with manual transmissions. What is your overall first gear ratio and how do you like it?

Garys 68

What engine, cam, etc...How do you drive the car, DD?

gkull

I have a 3.55 rear now and the tko500 would be nice because it would be easy to take off.

transmissions have a tq rating. Your buddy using a T-5 is skating on very thin ice

MIKE80

I went from a stock 4 speed to a T56 6 speed from a 94' Trans Am and have a 3.70 rear. T56 Gear Ratios : 2.66, 1.78, 1.30, 1.00, .74, .50. Tires are 25.55" tall.

http://forums.corvetteforum.com/c3-t...gs-list-7.html

drwet

Yeah, no kidding. He actually keeps a spare transmission rebuilt and ready to go. Problem is its a 4x4 so there aren't a lot of options for transmissions. He can have the Camaro gears installed in the S-10 case which will solve most of his problems, but that's an expensive wya to go. Its cheaper for him just to swap the trans every time he blows it up.

drwet

So that gives you a 9.85:1 ratio in first gear. How do you like it, and how much motor do you have in front of it?

MIKE80

I like it a lot! I never had it on a dyno, 385 stroker. I know someone with very close specs to mine came in at 525hp, so I'd say close to 500 is a good guess. I have 275/40 ZR17 Nitto NT555 Extreme Performance tires and can't hook on a launch.

Here's a short video I did 0-70 feathering the throttle from a stand still.

zwede

I have the TKO w/ 3.27:1 1st and 3.08 rear gears, 27" tires. It works OK, but I'm strongly considering going to a 3.55:1 diff. City streets tends to lug the engine @1500 rpm. 5th is only usable above 60mph. I'm thinking 3.55s would be perfect with a TKO.

Una4dbl55

not in my Corvette but in my 55 bel air I have the TKO500 with a 3.42 rear gear and couldn't be happier, drivability is good all the way around, good on the highway too,

I would say thats a good choice but then thats just me going from a muncie and a 5.38 gear, (which was a ton of fun but you couldnt go anywhere).

good choice with the TKO and 3.42 (and your 3.55 is close enough)

drwet

Thanks. I'll let you know how it works out in about six months.

Ibanez540r

I'm a little surprised by all of these responses. I'd have thought 11.6 would have been looked at as way to steep. I'm use to seeing responses about the TKO 600 for 3.36 and above and the 500 only for 3.08 and numerically lower...

gkull

I have the TKO 600 with 2.87 first gear and I had 4.11 rear end and it could take off at idle from a dead stop with my 434 ci with nearly 600 foot pounds of TQ. Really nice!

That is a ratio in first of 11.7957. fly wheel weight and engine tq all come into play. But anyway when I installed 3.55 gears the take off actually sucks! I have to slip it to get going which translates out to additional clutch wear.....................

iokepakai

Swapped in a Richmond 6spd with a 1st gear ratio of 3.28.My rear gear is a 3.08.Makes for quick start offs no issues.Better than an M-21 or M-22 Muncie trans 2.20 1st gear and a 4.11 rear gear. The 6th gear .76 OD is usable down to 45mph without lugging the engine.Decided on a 6spd over a TKO because of the closer ratio's.Had a Mustang 5spd with similar ratio's to a TKO500 and never liked the 1-2 upshift,lost to much RPM's for my tastes.If you have a torque monster,it's probably not an issue....The Richmond bolts right up is close to the same length as a Muncie and TH350 trans.Used a Gforce cross member ,and with a little trimming bolted right up to the trans.

drwet

What are you running for an engine? More importantly, what cam are you using, and what is the weight of your flywheel?

gkull

I have the TKO 600 with 2.87 first gear and I had 4.11 rear end and it could take off at idle from a dead stop with my 434 ci with nearly 600 foot pounds of TQ. Really nice!



solid roller cam with 7500 rev limiter. Weight of the fly wheel is only part of the story. It is the total weight of the rotating assembly. From the damper pulley to the Pressure plate fingers.

So lets say that we have two identical power and TQ 383 stroker motors build.

Motor "A" has a 400 journal externally balanced cast crank. the damper weighs 11 pounds, the crank 58 pounds and they installed a 15 pound super light weight aluminum flywheel. total of these parts is 84 pounds

Motor "B" has a 4340 small journal internally balanced. The fluid damper is small diameter 6 pounds, the crank is 42 pounds, an they install a 30 pound steel flywheel for a total of 78 pounds.


So if somebody tells you that they bought this 15 pound aluminum flywheel. I would say great, but it is still not as light as my setup with a heavier fly wheel.

Actually in my case I have a 22 pound steel with the 42 pound crank tiny 6.125 damper with a aluminum damper pulley. So I have about 70 pounds of rotating weight. compared to the more common people that end up with 80+ even with their 15 pound aluminum flywheel.

The other thing is my car is 300 - 500 pounds lighter than most stock vettes and about double the power. I like gearing that you can just let the clutch out and go and then use all motor roar off. go to a gear ratio and tire diameter calculator. If you have gearing that can go 55 mph in first gear it sucks because you are going to be slipping the clutch