Hey,

My car is a 1991 Formula, all stock, 305 with a 5 speed. Hopefully next year I will be putting in a new engine, probably a 383, if my budget allows.

If I did get a crate motor the HP would be somewhere from 400 to 500 horses, so naturally the T5 has to go (among other things).

The obvious choice is the T-56. I need a manual, and six gears would be awesome, even if the engine swap was indefinately delayed. I just have a couple questions:

-When checking around for T-56's, what should be included to make the swap into a 3rd gen as easy as possible? Bellhousing? Shifter? As you can see, I have no experiance in auto mechanics, I just love to drive. I plan on taking it to a GM dealer and saying "Here, install this". What parts can I buy to make this as simple as possible? Any rough estimates on how much such a swap costs (labour)?

-How much does the 2nd overdrive help on gas mileage? If I do drop a 383 in, possibly carbed, into a daily driver, this obviously becomes important. I understand the rearend gears also play a roll in economy?

-Most importantly, will the T-56 hold up? Given the bracket of 400 - 500 HP (I guess the torque would fall in there somewhere too then), will I shred the T-56? I'm not a drag racer, but I will not be sunday cruising a car with that kind of engine in it. Will I need a kit to beef it up?

-Stupid question: Do tranny's come with clutches? As in, will I have to get a clutch kit in addition to the T-56? I've heard good things about Centerforce and Ram, any further recomendations?

Please help me learn as much as I can about these cars.

Any responses would be appreciated, the more the better!

 

There are two tech articles on this site. One deals with a T56 into a car with a T5, the other deals with a T56 into a car with a 700R4 automatic. Read them both, and they should answer your questions. If not, search this board and read the hundreds of other threads on this topic.

You need EVERYTHING you can get your hands on from the donor car, and then you need a way to convert the speedo signal to one your computer can understand. It's all talked about in the tech articles.

Welcome to the website!

 

Hey,

I read the article in full and now know what I need, sorry I hadn't done that before.

But I'm still wondering, how strict is the "manufacturers guideline" of 450 TQ? Am I to assume that anything over 450 will lead to a premature transmission failure, and before even running an engine with that kind of power, I should have it built?

I know there are lots of kits out there for such a purpose, but I haven't seen one for a six speed, any recommendations to make it totally bulletproof? I have seen trannys that come already built up, but those are expensive! (gotta pay to play, i know)

Finally, would you recomend an aftermarket clutch kit with a T-56, or is the existing unit capable?

Thanks for any suggestions!
Cam

 

Rockland Standard Gear in New York is one of the T56 experts. http://www.rsgear.com/

450 TQ is a guideline, but no it wont fall apart on you if you're making 451 TQ.

McLeod clutches is what I recommend.

 

Well you can always run the stock clutch until it burns up and then upgrade. If you're worried about hitting the 450 ft/lbs then the clutch will probably go before the tranny. They have been know to handle a lot of torque even in stock form. I think their biggest problems are the stock sycronizers and stamped keys. Both can be upgraded for a few hundred bucks.

 

Hey,

OK, so if we assume the engine can pump out 500 ft lbs of torque, what all should be upgraded (synchronizers and stamped keys noted) in the transmission to make it withstand this power?

Also, I understand that 4th gen rearends are a bolt in mod for our cars. But what kind of rear ends do they use - are they more capable of handling big torque then the 10 bolt, or should I just follow the technical article on here for beefing up the 10 bolt (I can't afford a modded 9" or anything else).

Thanks for the help,
Cam

 

The biggest upgrade is the steel 3-4 shift fork to replace the aluminum one. Other than that, check out Rockland's website and call them.

4th gen rear ends are exactly the same internally as our 1990+ 10-bolts. Same 7.625" ring gear, same 28-spline posi unit. The difference is the 4th gen unit is 2" wider per side. People go with the 4th gen unit because they're easier to find with better gears and disc brakes than thirdgen stuff is.
The earlier thirdgen 10-bolts use 26-spline posi units and 7.5" ring gears.

 

If the tranny does not have any problems I'd say leave it alone, if the condition is unknown then you may want to tear it apart to make sure everything is okay. They are strong even in stock form and 450 ft/lbs is somewhat of a conservative rating. They offer upgraded gear sets but the weak link seems to be the shifting mechanisms.

When I got my T56 the second gear synchronizer was shot so I upgraded all the synchronizers to the carbon fiber type. Two of the three keys on the 3/4 synchronizer were broke so I replaced them with billet keys. The plastic shift pads were burnt through so I upgraded them to the bronze pads. My aluminum 3/4 shift fork was okay but I upgraded to the steal fork anyway since they are prone to bending. I replaced the shifter cup since mine was egg shaped. The rear seal was leaking so I replaced both the front and rear seal. I also upgraded to a hurst billet plus shifter and put in some Royal Purple syncromax synthetic oil. This thing shifts like butter now.

The gears are bearing were in good shape so I left them alone. The rebuild manual actually says to not replace the bearings unless they are damaged.

 

Where did you find the billet keys, the guys around here want $70

 

Can't remember. Online some place. I paid $75. Ouch I know. I couldn't find them any cheeper. I just replaced the keys in the 3/4 syncro since they are the most prone to breaking and mine were already broke. I wanted to replaced the 1/2 keys but they are a different style and I couldn't find them. The 5/6 syncro used the same keys as 3/4 but I wasn't worried about them breaking.