If I were to convert to a t-56 transmission, what would be the pros and cons of it? I know that with the 6 speed i would have a lot less drivetrain loss, but how much less? Also, does an L98 have enough power for the 6-speed or is the 6-speed an overkill? I've heard that the L98 with the 6-speed has little to no drivetrain loss, so therefore with a stock 245 horsepower, how much would u take off of that for real wheel with the t-56. Also what kind of track times are you guys getting with the t-56, and how do they work on the street for roll races etc.

 

You arent going to change the drivetrain loss, yes it will likely be a small bit more than your auto, but not by much, the conversion isnt for someone just looking to magically free up some power.

However, it is a good deal stronger than your existing transmission, has better gear ratios, and an extra overdrive, and manuals are a lot more fun to most of us.

 

What i'm really trying to figure out is how do they drive? It would be REALLY helpful if someone were to have a video of their 6-speed l98, but I wouldn't mind an explanation. Like where does it start to lose power in the 6-speed, would i want to upgrade my gears to 4.10s(I have 3.73s now)? Is it more gas efficient, does it all work correctly in an l98, how much money would it cost for the whole swap? I know on fbodymotorsports.com they have the transmission with most of the stuff you'll need for the conversion for like $1,800...is there anything else I would need. I would really love for my l98 to be a 6-speed, as I love to drive manuals and autos kind of feel restrictive.

 

It drives fine, it would be similar to a 305 5 speed car, my 92 heritage is a G92 5.0 5 spd, quite peppy, no match for an LT1 / T56 in a thirdgen, but it still nice to drive, definetly a lot better IMO than an auto, in your 91 you need the transmission, bellhousing, clutch fork, flywheel, clutch assembly, master and slave unit, from a 4th gen, additionally you will need spohn or skulte T56 crossmember, an SGI-5 box from dakota digital, and a manual thirdgen shift plate with boot. You can use the stock shifter from the 4th gen, however I would strongly suggest going with an aftermarket from Pro5.0. Installing a good aftermarket clutch wouldnt be a bad choice at the time of install also.

Pedals you can use thirdgen or 4th gen.

3.73's will work well with the T56, you *could* go with 4.10s if you really wanted, but i'd suspect the 3.73's will work better with the TPI motor. You *should* get better mileage than you currently get since your best overdrive is .74 and the T56 6th gear is .50, not to mention you will have less overall drivetrain loss, and no converter slip when getting to cruise speed.

 

What exactly is the SGI-5 box from dakota digital?

 

It will allow you to reduce or overdrive the signals from a speed sender, the T56 VSS pulse rate is much higher than the signal from a thirdgen transmission, this is used to reduce the pulses and correct your speedometer and vss input to the computer.

 

id say go for it...its really is one of the best mods you will ever do to your car. i did it to my 91Z exactly a year ago from yesterday in my driveway with the car on jackstands haha... i hope you have patiants cause getting that damn old 700R4 outta there is a PITA ( a lot of twisting and pushing/pulling) and since you have a electronic speedo the wiring is pretty simple. everything else is a breeze as long as you understand the mechanics of installing a manual or you've read some of the tech threads all over this website about the T56 swap. but like i said, its well worth it and you will be extremely happy when u can shift your own gears especially having a 350...next step get some 4.10's