455 and the Super T10

Is it fair to say a super T10 from a 1980 z28 with a 3.42:1 gear set would not work well behind a 70' 455?

Has anyone run this setup?

Changing the rear end gear ratio to make this work would not be a problem. 1970 Skylark street car.

Thanks.

 

I have had a Super T10 from similar year Z28 behind the big block in my convertible for 10 years with no issue. Mine has the 2.88 first gear and 3.42 rear gears. I rebuilt it before I installed it. I don't race it at the track or use sticky tires on it but have driven it hard on occasion. It's probably not the best choice if you plan on running it hard often. My dad ran a rebuilt T10 behind a big block for a for a few years in his car before switching to a Muncie M23 with no problems.

Ken

 

Thanks Ken, that was great to read. My drive ability will be similar to you and your dad.

 

Is it true the numerically higher (more teeth) the first gear ratio is on the super T10s equals a weaker trans?

If my calculations are correct, this would be decent.

New first x existing first (th350) / rear end gear ratio = the type of drivable gear ratio it has?

3.42 x 2.52 / 2.73 = 3.70

 

launch ratio should be around 10 - multiply fist gear X rear end ratio
so a 2.90 rear but that ration may not exist.
3.07 or 2.73 would work

Yes the 3.42 first is more likely to break.

 

I have a second design Power Brute ST10 series U with the 3.44 first gear, and nodular iron case. Swapped into the car by the original owner after he went to a 2.56 rear (now has a 2.73). He towed his 5000# boat/trailer about 100,000 miles with the car making many summer trips to somewhere in Canada from Stockton, CA. He essentially went to a poor man's overdrive for the fuel mileage. Anyway - it's been in the car for probably 45 years, or whenever BW first marketed this transmission. Drives great, still gets excellent FW mileage and horrible in town mileage. LOL. I had an input shaft failure about 25 years ago that I think was really a defect. I don't race the car but I'm not at all afraid to lay into it.

 

I had a Super T-10 behind a mild 455. Drove for a couple of years with no issues and some pretty significant abuse.
Then one day I was driving normally through a parking lot and out of the blue it just broke.

I would say if you have one - use it. You may be fine. I wouldn't buy a new or used one though. Instead I would go with the M23 and an iron mid-plate or a TKX.

 

you would be wise to tear it down and inspect it. then order a good rebuild kit + any other parts that show wear. maybe you will get lucky and only need rebuild kit about 250 bucks. if you have basic mech skill they are easy to rebuild. check out 5speed.com . no matter how well it ran in the last car it was in' its still a 40+ year old trans

 

I have used a Muncie M-20 (wide ratio) in my 455 convertible for years while racing it hard at the GS Nationals as well as the Pure Stock Muscle Car Drag Race in MI. I have broken a few and had them live for many years without issue. What breaks them is the torque. The broken transmissions were a result of power shifts at 3000 rpm where the engine tends to make massive doses of torque. I never broke one while shifting at 5000 + rpm where horsepower is high and torque is down.

The low 1st gear is a real treat on the street since it allows the car to get moving from a dead stop much easier and is much easier on the clutch.

Depending on what year Muncie that you are replacing you may need to change the yoke on the driveshaft to match the output shaft of the transmission.