TKO600 or T-56 Magnum for LT4 Supercharged 69 Camaro

[Cameron Ross]

I now have a LT4 Supercharged engine for my 69 Camaro and am trying to decide what gearbox to run - either a TKO600 or T-56 Magnum??
Here in New Zealand we don't have big long highways and I've heard other vehicles with 6 speeds don't get into 6th.
For the type of HP these LT4's which one should I run with?

[Schwartz Performance]

T56 Magnum hands down.

[BonzoHansen]

Here in New Zealand we don't have big long highways and I've heard other vehicles with 6 speeds don't get into 6th.?

Depends on your rear gearing

[jprewitt]

I second t56 all day long. Drove my buddies super fast 700hp Shelby Cobra with a custom built tko and it just hates to shift at high rpm. He has broken the shifter twice at COTA.

I pulled the trigger and got a magnum for my 68 this year and couldn't be happier. Shifts like butter at 7k rpm. Works perfectly with my 4.10 gears.

[TheJDMan]

I would also vote for the T56 Magnum. If I recall the Magnum is rated at 700 lb-ft where the TKO600 is rated at 600 lb-ft. There are two different OD gear sets for the Magnum .74 5th / .50 6th and .80 5th/.63 6th. I have the .80/.63 ratio with 3.90 rear gears.

[Nicks67GTO]

T56 Magnum without question. I've driven both. It's not even close. After racing and driving a buddies chevy2 with a t56 magnum for a week on cars and cones I was sold. It's the first time Ive ever even considered cutting up my 67 GTO for a mod.

[Cameron Ross]

Thanks for your replies guys. Not too many pro touring advice down here so much appreciated. I'll be running with the T56 Magnum.

What gears should I run in the rear? I have a Art Morrison full chassis with IRS and Dana rear end.

[andrewb70]

Thanks for your replies guys. Not too many pro touring advice down here so much appreciated. I'll be running with the T56 Magnum.

What gears should I run in the rear? I have a Art Morrison full chassis with IRS and Dana rear end.

What height rear tire will you be using?

Andrew

[68Formula]

What height rear tire will you be using?

Andrew

And wide or close ratio gear set?

What's the use? Road Race, Autocross, land speed records, cruiser?

[Cameron Ross]

And wide or close ratio gear set?

What's the use? Road Race, Autocross, land speed records, cruiser?

I will be running 26" or max 27" rear tire.
The car will be more of a street and sometimes track use when possible. The roads down here are perfect for driving - almost like a track with long sweeping corners and tight bends too.
Should I run with a close or wide ratio gearbox? The reports around are quite mixed...
What would be the best rear end ratio be for this package - LT4 with 650HP and T56

Thanks a lot for you input guys. I'll send pics once the we start piecing everything together. Body came back from strippers yesterday and should be looking to cut out floor and lower it onto chassis in a week or so.

[Schwartz Performance]

In my opinion, close ratio magnum with a 3.70 gear if 26", and a 3.90-4.10 if 27".

[Craig@Bowler]

In my opinion, close ratio magnum with a 3.70 gear if 26", and a 3.90-4.10 if 27".

First off my apologies on how crammed together the data is. It will not format the way I want it to in order for everything to stay nice.

I agree with Schwartz on the gear ratios and transmission gearing. If it is any help here is a break down of MPH vs. RPM using the close ratio T-56.

Here is the spec with a 3.70 rear gear and 26" tire. The RPM is the top number, MPH are in the columns under.

gear 1800 2000 2200 2400 2600 2800 3000
1 14.14648206 15.7183134 17.29014475 18.86197609 20.43380743 22.00563877 23.57747011
2 21.14024848 23.48916498 25.83808147 28.18699797 30.53591447 32.88483097 35.23374746
3 28.94587869 32.16208743 35.37829617 38.59450491 41.81071366 45.0269224 48.24313114
4 37.62964229 41.81071366 45.99178502 50.17285639 54.35392775 58.53499912 62.71607049
5 47.03705286 52.26339207 57.48973128 62.71607049 67.94240969 73.1687489 78.39508811
6 59.72959094 66.36621215 73.00283337 79.63945458 86.2760758 92.91269702 99.54931823

Here it is again with a 4.10 gear and 27" tire. If you would drop down to a 3.90 you can gain a few MPH in each gear at the same RPM.

gear 1800 2000 2200 2400 2600 2800 3000
1 13.25735045 14.73038939 16.20342833 17.67646727 19.14950621 20.62254515 22.09558409
2 19.81154618 22.01282909 24.214112 26.41539491 28.61667782 30.81796073 33.01924364
3 27.12657862 30.14064291 33.1547072 36.16877149 39.18283578 42.19690007 45.21096436
4 35.2645522 39.18283578 43.10111936 47.01940294 50.93768652 54.85597009 58.77425367
5 44.08069025 48.97854473 53.8763992 58.77425367 63.67210815 68.56996262 73.46781709
6 55.97547969 62.19497743 68.41447517 74.63397292 80.85347066 87.0729684 93.29246615

And as a final comparison just to see the difference the transmission gear set makes. Here is the breakdown of the wide ratio with a 4.10 gear and 27" tire.

gear 1800 2000 2200 2400 2600 2800 3000
1 11.8735866 13.192874 14.5121614 15.8314488 17.1507362 18.4700236 19.789311
2 16.79264391 18.65849323 20.52434255 22.39019188 24.2560412 26.12189052 27.98773984
3 24.15380288 26.83755875 29.52131463 32.20507051 34.88882638 37.57258226 40.25633813
4 35.2645522 39.18283578 43.10111936 47.01940294 50.93768652 54.85597009 58.77425367
5 47.65480027 52.94977808 58.24475589 63.5397337 68.83471151 74.12968932 79.42466712
6 70.52910441 78.36567156 86.20223872 94.03880588 101.875373 109.7119402 117.5485073

[Cameron Ross]

Thanks so much guys. Your all a massive help.

[Tweak]

Join our page mate
https://www.facebook.com/groups/937779519731180/

[Kenova]

I have spent a lot of time with this calculator. It's easy to input and change information.

https://weddleindustries.com/gear-calculator

Ken