I understand, I did the same thing, already had my axle with 3.73 and never changed it.

I have a LS1 T56 F-body (2.66/1.78/1.30/1.0/0.74/0.50). Upside of 3.73 is it places the engine near 2000 RPM at all the typical speed limit intervals (25, 35, 45, 55, 70 mph). The main downside is I have to slip the bejeebers out of my clutch in stop and go traffic. My engine and clutch combo will not idle-walk with those gears and my clutch wore out super fast from over heating. If your combo idle-walks then you'll be fine.

 

FYI - Part of reason for that is because I fell for the current fad of using a lightweight flywheel. My suggestion is do not fall into that trap, it causes nothing but pain for a street car.

 

Ever have one of those days where for whatever reason you consistently screw up one littel thing? Yeah, this is one of those days.

I fixed the TKX missing first gear stuff. When I added them I deleted one two many columns so 5th gear became the reverse gear.

But its all good now, and I set it to your settings, 18085 TKX, 3.73s, and 245/50/16's.

So, once you make a copy, you don't have to change anything. You can delete the older copies you made. Since I use this sheet for multiple cars, so i'm in there every month switching options around to get the Gear vs MPH by RPM charts.

 

Hell, my car won't idle in 1st gear without bucking like a bronco unless I keep it above 2000rpm, and I have a stock LT1 flywheel. Seems fine for a bit, then jerks around something fierce. Thats mostly idle tuning I think. Pro tuner, or maybe a better EFI system could tame it. as I still have about 17"in vacuum around 1000rpm. Its enough to run power brakes, but just about barely. Hell, my car doesn't even have the vacuum reservoir anymore, it broke long ago so I actually omitted the ball all-together.

I had considered a lightweight Fidanza 11lb flywheel, but glad my budget got consumed by other things lol.

 

QwkTrip

Thanks for your time

18085 is the ford version
17805 is the GM version

 

The 3.27 1st gear is meant for the majority of cars that pretty much just cruise and go to shows. It's got a more aggressive 1st gear to help a car with freeway gears get moving off the line. The compromise is a big 39% spread on the 1-2 shift that drops the engine too far for performance driving and [most people don't realize] also contributes to tire spin going into 2nd gear. Car will perform better and tires hook up easier at full boogie with a high rpm, quick, and tight shift.

Between the two other options with 2.87 1st gear, each gear change is,

1-2.....2-3.....3-4.....4-5
-------------------------------
34%...32%...22%...19%
34%...32%...22%...32%

19% overdrive is too tight in my opinion and will leave you wishing for another gear, especially considering it's only a 0.81 ratio. That's not even as much overdrive as a T56 5th gear (0.74). You'll be putting pointless wear on your engine revving it waaaaay higher than you want.

32% overdrive is a huge drop from 4th gear and is the same spread as the 5-6 shift of a T56, but not as deep a final ratio. I think it's going to be really annoying and create a "no-man's land" on 55 mph highways because 4th gear will be too high rpm, but 5th will drop ridiculously low. It's just begging for a 6th gear in between....

This is why I recommend and think you'll be happier with a T56 6-speed. Not only do you get tighter overdrive spreads that are more practical, but the final drive (0.50) is lower than any of the TKX transmissions giving you improved interstate cruising. Basically 5th gear will end up being your highway gear (55 mph), and 6th gear will end up being your high speed interstate gear.

If the TKX has a 6-speed option then maybe post up those gear choices so we can walk through those too.

 

Same. Are you using Tony's RPM carbon clutch? My car chatters in 1rst and is hard to get going. More rear gear will help this. Although, the chatter has lessoned as I've put miles on the car.

 

Yeah, a lightweight flywheel will absolutely necessitate a lot of extra work to tune idle. And it's a much more difficult job than normal because of the quicker engine ramp rates and tendency to overshoot idle.

And the clutch will wear out much faster because you'll have to slip it a lot more on an every day basis. My first Ram dual disc clutch lasted a whopping 5K miles. I just inspected an RPS carbon clutch with aluminum flywheel that was end of life at 12K miles. People are always quick to brag about good stuff but don't talk much about the dark side of the hobby and the pain they go through....

 

Never use a Lightweight Flywheel on a Daily Driver!

Stop and Go Traffic is HHHHEEEELLLLLLLL!!!!

 

I've got a RAM dual disc RTrack, comes in around 40 lbs complete. Too much slipping needed on the street with my engine, I'm killing it. I think Tony's lightened RPS assembly comes in around 26 lbs complete?

I just looked at a "lightly used" RPS aluminum from a Miata LS3 with 12K highway miles that was used mostly for road trips. Older guy, seriously light car that is driven easy. Clutch worn to end of life. I spoke directly to an engineer of the company that makes the RPS clutches (turboclutch.com) and he wasn't surprised at all because it's getting the crap slipped out of it just to drive normal. Lightweight flywheel is for the track, not the street.

 

this whole conversation makes me glad I went with nodular iron 🤣

at the time it was just a price thing, but shoot, dodged a bullet there!

 

I'm not sure what my RPS flywheel weight is. It is steel, but with lightening slots machined towards the outside. It doesn't lighten it much statically but it greatly reduces the rotating mass. First gear can suck sometimes, but it does drive nicely. I couldn't live with a aluminum flywheel.

Edit. Tony's RPS clutch is 33lbs all in.

 

Yep, you're right. I think I had aluminum on my mind earlier.

 

TKX does not, but it's just a hop-skip to the Magnum-F, which is is a T56 case, but internally it's basically a TR6060. Good to 700lb/ft and 8500rpm shifts.

The Magnum-F is what's going into my GTA, because whatever engine I build next will rev to at least 7500rpm. I want to build an engine that makes power all the way up to 8000rpm if I can, but 7500rpm is a more realistic number.

 

Is there a better option with the T56 that would work with my 3.73 gears?
Daily driver, cruiser use.

 

I forgot you would need a LT1 car transmission with input shaft for SBC engine. Those gear ratios can be different than the LS car transmission I referenced earlier. The T56 Wiki has a list of gear ratios by application, https://en.wikipedia.org/wiki/Borg-W...6_transmission

Looks like there are maybe 3 different gear sets for the LT1 Camaro/Firebird cars (1993-1997). I don't know how common each is.

3.36 / 2.07 / 1.35 / 1.0 / 0.80 / 0.62 (M28 transmission 1993 only)
2.97 / 2.07 / 1.43 / 1.0 / 0.80 / 0.62 (M29 transmission 1993 only)
2.66 / 1.78 / 1.30 / 1.0 / 0.74 / 0.50 (1994 - 1997, same ratios as LS1 cars)

Percent change with each shift in same order is,

1-2.....2-3.....3-4.....4-5.....5-6
----------------------------------------
38%...35%...26%...20%...23%
30%...31%...30%...20%...23%
33%...27%...23%...26%...32%

 

I'd probably be purchasing a new one

 

I don't know what gear ratios come in the aftermarket T56 for SBC engine. Its not necessarily the same as production F-body.

 

I had a TKO 600 in my last Iroc. Wide ratio w/ 3.42 gears, so not apples to apples. The 4 to 5 spread was way too much for me, though I could comfortably cruise on the highway. I'll never NOT do close ratio in the future, though I'd also go with 6 gears. I'm looking to offload my stock t56 and go with a new Magnum.

 

SBC style or LS engine style?
Not trying to play match maker... but you might have the trans BigBlock73 is looking for

 

Yeah I saw that.....It's LS style. I think you can make it work, but I got a guy lined up I think. Thanks though!

 

Almost all the New Ones that I ordered for Customers had the 2.66:1 Gear-Set for 1st through 4th...
Then usually there is a separate Option just for 5th and 6th, but I almost always Ordered 0.74:1 and 0.50:1 Gears.

I always either Upgraded all the Sychro Assemblies or had Face-Plate or Dog-Rings Sets Made.

 

Interesting article I found
It shows the T56 was put in Camaros with 2.73 and 3.23 gears in 1993
https://www.motortrend.com/how-to/ev...ur-gm-project/

 

the M28 (3.23) and M29 (2.73) gear sets only came in 1993 cars.

that’s where my t56 came from. I have the wider m29 transmission with the 3.36 1st gear.

the jump from 1st to 2nd is huge and really sucks.

plus the 93 transmissions are weaker, 350lbft, the later 450lbft ratings.

 

I have a 96 (I think) T-56. Has the 2.66 1st gear. Has the weenie stock rear gears for the car, 3.73. That rear gear was more or less OK from a stop with the original T-5 1st gear which was around 2.95.

Having had any number of 60s & 70s vehicles with 4-speeds, I'll comment that the 2.6x/3.73 ratio combination is essentially identical to a 69 Chevelle SS, 79 Z28, 68 442, and a handful of other such. Muncies and T-10s were both made with ratios like this. This combo was considered "entry level" and "wide ratio" at the time. People would take those cars and put 4.56 gears into them to get them to launch. The more serious track junkies would put in a "close ratio" transmission (a 2.21 "rock crusher" for example) and 4.88 or even higher rear gears. In my car, with a 305, the 2.6x/3.73 combo was even worse than the old muscle cars with big blocks: it was really limp off of a red light.

Having the 2 overdrives was cool on the highway. However, 6th was all but useless at less than 80 MPH. The car couldn't go up even a slight incline, had to downshift at least to 5th. Granted, it was only a 305 at the time, and only made 238 HP and 273 ft-lbs to the wheels; but still.

If I was building a car and could pick out the gear ratios I would consider ideal, in most cases I think it would end up something about like the 2.66 –> 0.50 combo, but with 4.11 or 4.33 gears. The spread between ratios is about right for a typical street motor's torque curve, but the higher rear ratio would help low-speed performance which REALLY is important with a stick shift on the street, while keeping the cruising RPMs reasonable.

 

To the OP. Your budget might dictate whether you can do a 5spd vs 6spd.

but if you can do a t56 with the closer ratios you’ll love the acceleration over a wider spaced 5spd.

 

I keep forgetting that my experience is not normal experience. With a 427 there is no such thing as not enough torque, even with bad low-rpm manners. I idle at 1000 rpm, yet I can climb a hill or pass cars in 6th gear at 1300 rpm. I don't necessarily want to be that low of an rpm, but it will do it if asked.

 

I do not offer anything less than a 4.30:1 Ratio Rear with a 0.50:1 6th-Gear.
The 2.66:1 Gear set loves a 4-Series Gear set! 4.55:1s are great too!

 

I just finished a t56 swap on my 82. It has a zz430 w a ram dual disk, a close ratio magnum F and a 9 inch w 4.11s. So far it's perfect. The close ratio w the 4.11 allows you to really rip through the gears. It's nice and tight. I'm breaking in the clutch still so no crazy stuff yet but this combo is great so far.

 

After a lot of time working on house projects I decided, after many conversations with Jody from Jody's Transmissions to go with the TKX.
TKX TCET17805 GM 600lb-ft 26 Spline 2.87- 1.89-1.28-1.00-0.68
He put together a kit using his experience and vast knowledge of what works.
Jody is great to talk to and provides exceptional customer service.
I will start new treads going forward with questions that arise.

Thanks for all the time and advice