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Hey all. Just crunching numbers and trying to decide with to go with a T-56 swap to go along with my (soon to be) built 77’ 350 sbc or if I should get my T-5 built by G-Force Transmissions. I’ve got an 89 firebird with the 2.8 so I know I’ve already got a good bit in my plate as I’m not the most experienced, but was just wondering how much it has costed others to swap a T-56.
Also how the difficulty would vary between just swapping a bell housing for the T-5 to bolt to my 350 vs the T-56 and the new pressure plate, master cylinder, etc
A close friend of mine had a factory t5 built with a Geforce kit, Between the parts and labor it cost him just around 2500. For that money you may as well get a t56. Ive bought 2 complete t56s with clutch and hydraulics for 1600 each but to me it was a rare circumstance. The lt1 t56 will bolt right up to your 350
2 things to skip:
V6 T5 w/ V8. The gearing in 1st is short. And 5th isn't quite enough. A V8 T5 would be nice but may not be simple to find. I would consider a new Gforce case V8 T5.
94-02 T56 with talll gearing. If you have LT1 power or better, great. A stock heads 77 350 isn't going to warrant spending more to go T56.
If you're on a budget, spending more for 6th gear isn't going to pay off. Prioritize getting gearing right so the car is enjoyable to drive. And see what options are out there. I have had a V8 T5 with 3.73s and it was easy and fun to drive.
A low stall torque converter, a barely-enough 1st x rear gear total ratio manual, or anything that keeps an engine from getting into a good part of a torque curve should be avoided.
A close friend of mine had a factory t5 built with a Geforce kit, Between the parts and labor it cost him just around 2500. For that money you may as well get a t56. Ive bought 2 complete t56s with clutch and hydraulics for 1600 each but to me it was a rare circumstance. The lt1 t56 will bolt right up to your 350
my 350 is a two piece RMS so I would need to get a different flywheel (+$400)
What does G-Force charge these days? They offer DIY kits(or used to, if they don't anymore), or send yours in and they'll build it.
As for the cruising gear, G-Force 5th gear is .63, same as the T56 I believe, so any gearing benefit will occur between 4th and 5th with the T56, and that won't be much. G-Force used to also offer a .59 5th gear, maybe still if you were to talk to them.
I just noticed that Tremec is on Holley's list of brands. From what we've been learning about Holley in 2023, it's destroying all of its once good companies, so it might be a good idea for people to avoid buying new T5s or new T56s and rebuild older models. G-Force isn't on its list of brands, so that might be the better option, IMO.
It comes down to what YOU really WANT to do, what you have/want to spend, and how much work you want to do. A T5 is a one-man job. A T56, maybe not so much. Your car is already built for a T5, so you'll need basic swap parts. A T56, not so much. A G-Force T5 will handle almost anything you throw at it, but if you ever think you might go flippin crazy someday, then the T56 is the one for handling a 2nd childhood.
Personally, I like the G-Force, but I still haven't outgrown my 1st childhood and likely never will, so I don't see a T56 in my future.
03-04-2023, 12:13 AM
