TKO 600 vs T56?

[65ss]

Ok I know this subject has been explored before. I haven't seen this question answered before though. Have a 65 Malibu SS 427 BBC roller cam, mpfi consevitive 525hp 550tq. Would like a T56 with a 4.11 rear, but am worried that first gear would only last 30 feet, and with the close ratio wouldn't have enough time in between shifts. Anybody out there running a combo like this? Would a tko 600 with a 3.73 be a better idea? Wheres the best place to get a good T56? Thanks for humoring my redundant question.
T.J.

[65ss]

I guess my question is too vague. I just want to know if anybody is running a Big block, T56, and a 4:11 rear gear and how it's working out for them. Just trying to get my ducks in a row before I blop down 3g's I may regret later. Car isn't gonna see slicks more than once or twice, going to be more of a weekend daily driver. If anyone has an opinion I'd appreciate hearing it.
Thanks, T.J.

[JamesJ]

Well dont knwo if this helps but i dont think that you need a 4:11 It also depends on the size (tall) your tire is. here is a link to play with. http://5speedtransmissions.com/calculators.html
http://5speedtransmissions.com/gear_calculator.html
http://5speedtransmissions.com/startlineratio.html
http://5speedtransmissions.com/distancecalc.html


With the last one you can even see how far you will go 30 feet or not.

And i have never heard anything bad about this place. So you can get one here if you want

[XcYZ]

I guess it would come down to whether or not you think double OD is necessary as I think either transmission would live behind your setup. The 0.50 6th gear in a T56 is purely there for economy driving, so I'd say run your numbers in one of the many gear ratio calculators out there and see which tranny gear ratios would be best for you.

[65ss]

I have been running the numbers in a few calculators. 3.55 and TKO look good but going from 1.1 in forth to .64 in 5th looks like it hurts. T56 with 3.89 or 4.11 looks a little better plus the 1.1 to .74 looks a little more fun. I live in San Diego and will probably never hit 6th around here, maybe on a Vagas run or going to Pomona. I hated how soon I had to shift into second on my Super T-10, these don't look much better. Looks like about 20' feet for normal driving on the T-56 and 16' for the TKO. I like this site but it's starting to bum me out a little. Since I've been going through the forums I've found out my bumpsteer, and turning radius are going to be horrible. My Rear suspension is going to skip around corners due to it binding up, and I haven't even got the thing out the garage yet. Wish I had found this place sooner. Anybody know where I can find some spherical bearings to retro fit some Hotchkis lower trailing arms? Any body running the A/F/X spindles?

[JamesJ]

If you go over to pro-touring.com most likely you can search and find alot of info. Just read for about 13 hours and you will learn where you can get all kinds of pointless stuff.

[Y-TRY]

I don't know directly bewteen those two tranmissions but I want to pass on a nugget of experience:

When I built my car, one of the carry-overs from my old set-up were my 3.89 gears. I went from a Muncie 4-speed (2.56:1 1st) with 28" tires, to a TKO (3.27:1 1st) with 26" tires.

Like you, I was focusing on final drive ratio in top gear. With .68 overdrive, 26" tall tires (285/40/17) and 3.89's, they looked fine for the highway.

One of the first things to go, after ONE drive of the car, was the 3.89's. Not because of the final drive, but because of the gearing 1-4. Highway crusing was fine, though.

I guess my point is: Don't just consider the final drive. 1st gear was pretty much non-existant and I was shifting quite often. I swapped 3.25's in and enjoy the car MUCH more.

When calculating, I determined that the drive ratio in first with the new set up was the equivalent of keeping my 4-speed and 28" tires and dropping in some 6.14's or something crazy.

While cruise rpm IS important, it is no more important than the rest of the gears.

Good Luck. I hope this gives you something to consider. :thumbsup:

[65ss]

I've been worried about the 1-2 shift too. Problem is I already got rid of my Super T-10 and I'm not sure what the first gear ratio was on it, so I won’t be able to compare it to the others. The 2.66 1st on the T56 with a 3.89 is very comparable to your 3.27 1st with a 3.25 rear. The TKO’s 5th seems to drop off too much, going from a 1.1 to a .64. The T56 seems a bit better with the .74 5th. I wouldn’t be able to use the .50 6th around here very often, but it would be nice heading to Vegas. I still need a new rear so gearing isn’t set yet. Think I’ll just flip a coin at this point, seems either will work well.
Thanks, T.J.

[Y-TRY]

Yeah, it all gets to be academic at some point. I think that the physical strength is comparible between the two. The installation is about equal, what with Tito's install kit and the Tremec installation stuff. I second the idea that you'll hardly ever use 6th, though. If you ever put a rear gear in enough to need 6th, the rest of the gearing will be no fun. Even with 3.25's, I hardly use 5th (the big cam likes good rpm). And I'm shifting less often. The lower gears were the ticket with my car.

Mine works, at least in theory: I have a big-cammed, twin-turbo, manual transmission car. Shifting only slows the turbos. So I figure that 1st gear being so steep will get the tubos spooled pretty well and then the big drop from 1-2 willl let me take advantage of the spooled turbos and the full power curve. I see no less than 500ftlb from 3000rpm up.

As a matter of fact, I plan on experimenting with 1-3 shifts on the 1/4 mile. The idea is, that even if it wants to bog, I'm still making huge torque, and I will spend less time coming out of a bog than from trying to contain the spinning if I try to hit 2nd with full steam.

[USAZR1]

I'm running a 355" SBC/T56/4.11/26" tire combo and first gear doesn't seem very low at all. My car will easily pull 6th gear at 60mph,without lugging.

[Dezduster]

I have the tko with .82 over drive.It also has the 3.27 first. I was using 3.91 gear and I could 1/4 better using 2nd to leave in due to the first gear was so low,thats with a 28" tire. I swapped to 3.23 and I actually get to use 1st gear for a productive amount of time.
My engine combo is 422 ci small block run 115 in qtr @4500' 98 degree weather. In Sac I ran 117 throw out slav crapped and could not get 2nd,or 3rd gear well. I am getting 400 + or - to the ground. I cruise at 1600 to 1800 in OD @70. Hope this helps some on youre gearing ?

[JimM]

I put my new 383 sbc and tko 500 on the road for the first time last weekend.
Rear is 3.08. Even then, the 3.27 first is very very short. not a bother just cruisin from stop signs, but instant redline and tire smoke if I get into it in first. The 5th gear is pure fantastic. The drop from 4th to 5th is NOT a problem at all, and she tach's 2000 rpm @ 70 mph, smooth and quiet as a church. The closer ratios and taller first on the 600 would probably be better, but even then I'd keep the rear axle fairly low, no higher than a 3.55.

[speedshopmike]

if you're uying a fresh one or find one used, the aftermarket versions of the t56 have a 2.97 first and .82/62 fifth and sixth gear ratios (if i remember the exact numbers)
i run one behind a small block in an s10 (for sale!!) with 3.73's; it's great; pulls 6th gear from 40mph clean.
ratios are well spaced for fun, 5th gear fine all day from 30 up.