Tremec T K O transmissions

[bn69stang]

I am currently up grading to  t k o 600 with the road race 5 th / .82 and was planning to run 3.89 gearing , from a t k o  500 with 3.50 gearing , i was try ng to talk my friend out of some 3.91 s he s not using . I currently have 255/60-15 on the rear for tire s so say 27 inch , anyone running 4.11 s say with either a 255/60 or a 275/60 with this tranny and 3.89 s or 4.11 s , i would like to still have a decent 5 th for freeway spurts here n there .. Bud

[65er]

I have the .64 overdrive on mine with 3.89 gears and 255/60-15's.  Turning around 2000-2200 most of the time on the highway.  Calculating the OD ratio difference, you would be at 2560-2820 for the same speed, and up around 3400 RPM if you're going 80 mph.   Most of the time I feel like it could probably stand a few more RPM but maybe not quite as much as you're talking about.  Depends on how fast you usually go on the highway but if you're consistently over 60 or 65 I think you might prefer something closer to 3.50

[bn69stang]

I guess i could keep the 3.50 s and the trac loc setup , for serious roadtrips and run more gear in another center section for street/strip setup . In order to run 275/60 s i need to buy 2 - 15 by 8 magnums , but would gain tire height . Bud

[65er]

If you've already got the 3.50 gears ready to go I'd definitely run that a while to get a feel for it first.   I actually started out with a used 4.30 gear which was ok on the highway but I hated it in town.  After driving it a while I put in a used set of 3.82's and liked that pretty well so with that experience I bought a new set of 3.89's that seem like a good fit for my driving habits.

[sumfoo1]

this is why i went t56 wide ratio...  because i have your transmission... + a .50 over drive...

so with 391s my 500cid engine should be happy cruising at 80

[My427stang]

I run a TKO 600 with a .64 behind my 489 with a 4.10 and 275/60-15 tires, with my EFI and plenty of cubic inches I have zero issues with a 2.62:1 compound final in 5th

That being said, a 4.11 would be 3.37:1 with a .82 and a 3.89 would be 3.18:1.  Either of those would be perfectly happy crusing anywhere.  Compare that to what you have now .68*3.5 = 2.38:1 and you get a pretty big difference.

However, 1st gear with the 4.11 would be 11.79:1 and with the 3.89 would be 11.16:1.  The TKO-500 you have now is 3.27*3.50 = 11.44:1

I think I'd probably leave what you have with the 500, or go 4.11s and a .64 TKO.  That way you'd have about the same 1st gear, and still have a decent 5th gear.

[JamesonRacing]

Ross - I'm running a similar combo as yours, with a 465 roller cam engine, 0.64 fifth gear, 275/60-15 tires, but I currently have a 4.00:1 gear with a tru-trac.  I'm moving the tru-trac to a different car and have a locker to replace it for this car.  As the pumpkin is coming out to install the locker, and the 4.00s make a little whine on coasting, I got to thinking how a 4.30:1 ratio may work in place of the 4.00. 

Do you think that would be a good move?

Thanks!

[My427stang]

1st gear will be pretty short, but it should be a healthy car with that gear!

[Ratbird]

Hey Bud, just an FYI in case you're around this weekend. I plan on being at the strip Saturday for the "take it to the track" event. It'll be my first time on a drag strip ever. 11:00 - 4:00. Any advise on what time to be there in order to avoid the crowd?

Dave Jones

[fastback 427]

Good luck at the track this weekend! I'm sure you'll have a blast and will be " hooked"  pun intended. Keep us posted with times and such, interesting to see how she does.

[Ratbird]

Will do!

With Albuquerque being a mile high, and the car (currently) being a "one tire fire" differential, I'll be thrilled to get into the mid 14's.

Dave 

[bn69stang]

Hey Dave i would be there at least an hour early , i wont be able to attend we a death in the family but at least tex me and tell me how you did . or email me , i can hardly wait to take the stang out there .. sorry dude wish i could and good luck and be safe .. Bud

[Ratbird]

Thx Bud, I'll keep you posted.
My condolences to you and your family, very sorry to hear that.

regards, Dave

[bn69stang]

Thank you  Dave , we appreciate that and again good luck and be safe .. Bud

[2VNTG68S]

Very timely thread! I'm trying to decide on gears for my '68 Mustang Vert.  It will have a moderate 390 (415 hp/440 ft-lbs) and a TKO600.

Its going to be a cruiser for the most part but will see some highway time and the odd stoplight fun with the ricers.  What I want to avoid is a 1st gear that's too short and a 5th that will be useless below 70 mph.

Would you guys go with 3.55 or 3.80?

[My427stang]

2VNTG68S

I think you'd be happy with a 3.89 or 3.91.

[Cyclone03]

I have a TKO 600,.62od.
When I first put it together I had 4.11's with a 27" tall rear tire. I loved 1st-4th but, and this will sound odd, the drop from 4-5 sucked. I seemed to find myself shifting from 4-5-4 too much rpm, not enough rpm.
I went to 3.25 useless 5th gear below 90 lol. I'm happy with 3.70 no problem in 1rst,good 4th from 40-60, 1/4mile . .62/5th good from 50-up.

If I where to do it over I would do a 600/.82 with  a 3.50 or (NASCAR) 3.60 gear.

I think Richmond gear has an online gear ratio calculator go over there and plug in different ratios for rear gear and OD.

[2VNTG68S]

Thanks for all the feedback guys. I went with the 3.80's. Will let you know how I fare.

[Ratbird]

10.9 SLR will be almost ideal Bud, I like that number. Make sure you let us know how it turns out for strip racing.

With a 27 inch tire you'll be at 2327rpm at 60mph.  65mph will be 2520rpm. At least according to this calculator.

http://www.csgnetwork.com/multirpmcalc.html


Dave

[bn69stang]

Thanks for that link Dave , the gear ratio chart is very helpful .. Bud