kyeakel

I've been considering a 4 speed conversion. A forum member has a Z model 3.42 1st gear ratio, rated at 286 ft lbs of torque, the remaining gears are 2.28, 1.46, 1.00. I'm concerned that 1) 1st gear is too low to be useful, even with my 3.08 rear gears. 2) the 286ft lbs rating is too low for the ZZ4, which is supposed to put out 405ft lbs.

Would anyone like to confirm or contradict my thoughts above?

Thanks for your help,
Kipp

burners

I have that ratio version in my '70 Nova with a built 350. I can attest that it will take a lot of abuse. My Nova has 2.56 rear gears but I don't think 3.08s will be bad. A 3.08 with a 3.42 first gear gives a final ratio of 10.5. Compare that to a 4.11 with a 2.48 (from a TH350) and you get 10.2. So you really aren't that far off and it will accelerate real good in first gear. As long as you don't drag race the thing with slicks I think the transmission will hold up. Keep in mind that the Z gear version usually has a smaller Muncie/saginaw/TH350 output shaft so remember that so you get the correct yoke for it.

0Road-Race Vette

I had a zz4 motor and a super t10 in a 1980 Trans Am. Had the car 4 years, and I drove it!!!. Never ever had a problem. There is nothing to worry about.

Dantana

I built a 450 hp sbc a few years back and had a Super T10 in there with a .308 and I never had a problem. I believe those ratings are for 24hrs continuous use and not spikes? I ran a hayes clutch and always assumed I broke the tires loose before getting to the point where I would break the trans.

puts on a nice show too

63mako

No problem! That is a continuous 24 hr torque rating and a real good ratio for your setup. Think your car is a 350 turbo and the driveshaft and yoke should match. My ST-10 used a 400 yoke.

panic

Nothing to worry about, i have a 406 american speed 575hp engine and a fearless T-10...2 years of heavy right foot abuses and it's still there with no probs

kyeakel

Thanks guys, I didn't want to make a mistake. Sounds like I won't be.


Kipp

MotorHead

Here are my thoughts on the Super T10 tranny after breaking two with my my 406ci. It seems they can handle a certain amount of torque no problem. I can only speak for the aluminum case models, and they held up fine on my 355 with 330 RWT.

Once I put the 406ci in with over 400 RWT I broke one then another. Here is how I think they break. It is not from sudden impact such as dumping the clutch but rather, an extended period of high torque such as a second gear run from 2500 to 6000 RPM.

In that range my 406ci puts out over 400ft/lbs to the rear wheels or over 500 crank ft/lbs. Now what happens is the aluminum case twists and then parts and gears inside get misaligned and you blow that gear. This is just my own opinion, however I have heard this same line of thinking before on other forums.

burners

Motorhead, I agree but the part that seems to be weakest is the mid bearing plate. I think that is what distorts and causes things to fail. Keep in mind that you are making 510 ft/lbs at the crank. I think the little old ZZ4 isn't making enough torque to kill the tranny.

Brandywine

I ran the stock Super T-10 from my 1980 with a carbed and TPI'd ZZ4 for about 8 years. I finally wore the tranny out, but I don't think it was the ZZ4...I think it was old age.