which gears

[70rs]

Can anyone give me some direction on gear selection. 1970 camaro, big block(600+hp), 99% street driven,
I have not selected rear gears yet and need input on those but also with the TKO 600 trans. It is offered with two different final drive ratios. Can anyone suggest which one and which rear gears and tell me the pros and cons at the same time. Fuel mileage is not any concern.
Thanks for any help here.:cheers:

[Vegas69]

I thought you just borrowed Anthonys tilta whirl?

[70rs]

I thought you just borrowed Anthonys tilta whirl?

I did. But I still have a rear end to finish up and get under the car and will need to get the trans figured out soon enough too. Just making sure I have all the info I need when I need it. The rear will need to go under the car next month when it comes off the tilt a whirl. The old one is going by by soon.

[speedjohnston]

If you use this gear calculator you can figure out any configuration, gear, rpm with whatever tire size etc. that you want. http://www.5speedtransmissions.com/gear_calculator.html hopefully that helps.

[Vegas69]

I had to give you a hard time. 3.73 is what you want.

[speedjohnston]

If you don't care about milage and you want to keep on accelerating in 5th you would want the 600r with the .82 overdrive. The other one would be too big a jump from 4th and is more or less just for better mileage IMO. If you want different opinions on gear ratios you need to include tire size and what you plan on doing with the car, how fast you want it to go top speed, do you drag race and anything else that may help. :cheers:

[Vegas69]

I agree on the jump to 5th. The jump will be at exactly 130mph at 6000 rpm. :D The overdrive is really nice and he already said it will be a 99 percent street car.

[speedjohnston]

I agree on the jump to 5th. The jump will be at exactly 130mph at 6000 rpm. :D The overdrive is really nice and he already said it will be a 99 percent street car.

even as a street car he may have a top speed or max acceleration he wants to achieve. my buddy has a street only car (making over 800 hp to the rear wheels) so far and is changing the gearing so it has a top speed over 210mph in 5th... but with a 28" tall tire and wanting max acceleration in a drag race, street driven or not, a 4.30 gear might be better, depending on max rpm and would still have decent top speed over all in overdrive.
That all being said the 3.73 is a good all around gear that won't have the car geared too high or too low if 70rs doesn't have any other specific goals in mind. :thumbsup:

[awr68]

Eric, what size tires are you going to use?

FWIW, I am using a 3.89 rear gear, T56, and 335/30/18

[70rs]

Maybe I jumped the gun here because tire size has yet to be determined. I think I am runnin 18" front and 19" rears on it but do not have an exact tire size yet. As for what I want out of the car? Top speed is nice but not at the sacrifice of bottom end, I want a happy medium of both. I get a bigger kick out of launching from on ramps and out of corners than anything else. I don't see much if any drag racing (on a track anyway). I want a good balance of both. That is kind of the goal for the whole car, good handling without killing me by riding so rough, good braking, good speed, but overall balance is the goal. I will be using it as a road car and need to maintain a decent level of comfort for my wife and son. Balance is the goal.
Thanks for the input.

And Todd, giving me a hard time is welcome. But you will get it back.:D

[PASD U]

Wanting to learn something myself.

[Flash68]

With the TKO I would go no higher (numerically) than 3.50 or 3.70. I switched my 3.89s out for 3.70 also due to the TKO. With that kind of power and the short 1st gear of the TKO, this is what I would do if I were you. One reason I wished I woulda done the T56 in hindsight, but oh well.

And since it's a street car I would do the .64 overdrive - same as I did and for the same reason.

Anthony's setup of T56 and 3.89 is an ideal setup to me.

[XcYZ]

I'm pretty happy with my 3.70's, but I'm running a T56, so it's a bit different than the TKO600.

Since your BBC is going to make in the neighborhood of 600ft-lbs of torque, I'd lean towards gears in the 3.70 to 3.90 range with the size tires that you think you're going to run. I think that would be a great street setup.

[Payton King]

You need to figure what RPM you will be turning in your top gear at 65 mph. I can tell you from expirence that depending on your motor it could suck.

Although mine is completely different than yours, this is what I ran into.
I have 19s on the back with 285/30/19 I believe it is 27 tall. 3.80 gear and a T56. At 65 in 6th I was turning 1500 RPM. My car idles at 950. If anyone slowed me off of the 1500, my car would lug and I would have to shift into 5th. Big pain in the ass. Changed the gear to 4.11 and now in 6th at 65 mph I am turning 1750. Does not sound like that big of a deal but it is huge cruising on the interstate in traffic or trying to obey the law. I can slow to 55mph with out a down shift.

[Vegas69]

He's looking at a fairly radical camshaft so he will want to keep his overdrive in the 2000rpm range minimum with a big block chevy. Especially since it will be carbed. Mine is comfortable at 2k at around 60 mph. That makes it comfortable for most highway and all freeway jaunts. I agree with flash on the low 1st gear. I wouldn't want lower gears than a 3.73. I considered 3.55 gears but ultimately decided on 3.73 due to wanting to be in overdrive around 60 mph. The T56 is a whole different ballgame.