A non boat related/car engine & transmission ???

[n8dawg]

A friend of mine has a '72 GMC Sprint (basically a el camino for those of scratching your heads). He wants to put the 572 GM crate motor in it with a M-22 4-speed. I told him to spend a little more and drop in a Doug-Nash 5 speed, I know it will handle the horsepower, the racing shop is telling him to use an automatic. My thought is that he isn't building this car for racing, the stick shift is alot funner to drive around that an automatic. I grew up with the thought from my dad that ALL automatics are for old people..........keep it old school!!
Any thoughts on this?

[ck7684]

Depends on how well he likes rowing gears. I had a '65 Impala with a muncie M21 and racing clutch. It was fun sometimes, but when just cruising it was a PITA. I also had a '76 Stingray with a fairly stout SBC and racing auto trans, which was also a PITA to drive slow cuz it banged the gears so hard and so fast. If it was mine I'd go with the 5 speed...:D

[Badburn]

Personal Preference.......... I'd put a v drive in it:D

[Youngblood]

T-56 6 speed, might as well get decent gas mileage on those long hauls.

[tbanzer]

I put a automatic in my blown street rod. I figured it would be easier on drivetrain parts and also figured I would need two hands to steer.

[n8dawg]

I put a automatic in my blown street rod. I figured it would be easier on drivetrain parts and also figured I would need two hands to steer.
I see your point if the car is a daily driver but if not then why not have some fun banging gears out if the car is only driven on the weekends or once a month.

[ck7684]

Auto will definately shift faster if built right...

[n8dawg]

Auto will definately shift faster if built right...
:sleeping: But are boring to drive!......Personal prefrence:D

[N281PONY]

Like Youngblood said. I would look into a Viper spec T-56. Call D&D Performance and talk with them. That's who I order my parts from.
http://www.ddperformance.com/

[H2OT TIMES]

How about a built automatic with a manual valve body??

[curtis73]

The t56 won't like the torque. The best t56 will take 550 lb-ft, but anything that came in a viper or camaro will only really take about 450.
If you want more info, let me know. I just went balls-deep on a t56 build and might be able to help.
The 4-speeds might be a wise choice. A rock crusher (although probably more expensive than a viper t56) will take lots of abuse. The main thing that kills a manual's torque rating is the helical cut on the gears. They create linear force on the shafts and the torque from the engine literally busts the casting pushing the shaft right out of the case. Actual gear or shaft strength is rarely an issue.
The 572 will destroy a t56 in very short order if you have any shred of traction. Think of something a bit beefier.
By the way... the only real operational difference between a viper t56 and a GM t56 is the shift forks. the gearset, case, and other parts are identical. The front adapter plate, input shaft, the shift forks, and the tailshaft/tailhousing are the only real differences; the guts are the same. I just bought a viper t56 and converted it to fit a GM car. I replaced the front adapter plate, input shaft, and tailhousing, but I left the beefy viper tailshaft in place and bored out the GM tailhousing to fit a viper slip yoke.

[Youngblood]

The t56 won't like the torque. The best t56 will take 550 lb-ft, but anything that came in a viper or camaro will only really take about 450.
If you want more info, let me know. I just went balls-deep on a t56 build and might be able to help.
The 4-speeds might be a wise choice. A rock crusher (although probably more expensive than a viper t56) will take lots of abuse. The main thing that kills a manual's torque rating is the helical cut on the gears. They create linear force on the shafts and the torque from the engine literally busts the casting pushing the shaft right out of the case. Actual gear or shaft strength is rarely an issue.
The 572 will destroy a t56 in very short order if you have any shred of traction. Think of something a bit beefier.
By the way... the only real operational difference between a viper t56 and a GM t56 is the shift forks. the gearset, case, and other parts are identical. The front adapter plate, input shaft, the shift forks, and the tailshaft/tailhousing are the only real differences; the guts are the same. I just bought a viper t56 and converted it to fit a GM car. I replaced the front adapter plate, input shaft, and tailhousing, but I left the beefy viper tailshaft in place and bored out the GM tailhousing to fit a viper slip yoke.
That's funny, the (stock)t-56 in my 01 Camaro takes a steady dose of 750+ lb/ft! My car has a race weight of 3465# and cuts 1.35-1.40 60' times on a 28x10.5 drag slick.
You are correct about the viper/gm t-56's. The viper deal comes with a steel 3-4 shift fork and a larger 30t output shaft while the gm model comes with an aluminum 3-4 shift fork and a smaller 26t or 28t output shaft.
My car in action if you care to see it, http://www.tncperformance.com/pics/5dollarmilkshake.wmv

[curtis73]

That's funny, the (stock)t-56 in my 01 Camaro takes a steady dose of 750+ lb/ft! My car has a race weight of 3465# and cuts 1.35-1.40 60' times on a 28x10.5 drag slick.
I guess from the 60' times you get decent traction, which is a REAL testament to the fact that they must underrate the t56s big time.
Yikes :)
My personal thought is to do a REAL evaluation of the car's needs. The t56 (as has been shown is plenty beefy) is a great tranny, but with a hot 572 it can be super overkill. Consider the T56 much like a rock crusher m22 with TWO overdrives. You really won't be able to use it. You'll need 4.56s to adequately take advantage of the 2.66:1 first gear in it and you'll still be turning a low 2000-ish RPMs on the highway. Unneccessary if you ask me.
Before I can really recommend anything, tell me the cam specs, peak hp rpm, peak tq rpm, and weight of the truck. Then we can match a rear gear and tranny ratios that will fit. Choosing anything before that is ridiculous.

[n8dawg]

We ended up getting a Muncie M-22 "Rockcrusher".
Thanks for all the input guys! Now my buddy wont fall asleep driving it:D

[n8dawg]

Youngblood- Your car is cool, but I have found that you can't powershift a new car like you can the older Muncie trannys. There's nothing like the pressure of powershifting, if you don't get it just right your motor will be gone, unless you have a rev limit on it, but you see I don't like all that new tech. stuff...Keep it old school, fun to drive!!!!!!!!!

[pocketchange 22]

if you ever decide to add Nitrous, good luck trying to shift without parts ending up on the ground.