Ferocity02

iTrader: (59)

I picked up an F-body T56, going through it right now and inspecting it, and will be installing in a few weeks I hope. What gears are you guys running with this trans? My trucks is mostly a commuter/daily driver, will be turbo in the future with 500+rwhp. Looking for good fuel economy on the highway so I was going to choose gears based on cruise RPM. My tires are 285/50/20, 31.22" tall.

4.56 = 1718 rpm @ 70 mph
4.88 = 1838 rpm @ 70 mph
5.13 = 1933 rpm @ 70 mph

Right now I'm leaning towards 4.88. My truck cruises at about 2000 rpm now at 70mph.

Any of you T56 guys running a TrueTrac also? Is there a need for one with a T56 and 500+rwhp.

Thanks!

ak2007r6

iTrader: (1)

I would shoot Silverado_SS_04 a PM. I know he made the swap and can probably give you some good info

1969x11

iTrader: (38)

I was running 4.56's and a tru-trac with a 30'' tall tire. I think the 4.88's would be a perfect choice and def. get the tru-trac.

Boosted_Silverado

iTrader: (3)

i run 4.56 gears with a Truetrac in my truck, wheels are 285/35/22.

Ketis

iTrader: (2)

i have 3.73s in mine and its horrible.

i do have some 4.88s sitting in the closet though... along with a tru tac

just need to find someone to install it

275/45/20

Ferocity02

iTrader: (59)

Don't you have a Magnum T56? What gearing does it have?

Boosted_Silverado

iTrader: (3)

yes, i have the TUET11012

First Gear Ratio 2.97:1
Second Gear Ratio 2.10:1
Third Gear Ratio 1.46:1
Fourth Gear Ratio 1.00:1
Fifth Gear Ratio 0.74:1
Sixth Gear Ratio 0.50:1

PathfinderJr

iTrader: (6)

Running a GTO T56 here with the 2.97 first gear and 0.57 sixth gear. 30" tires, 4.30 gears, spinning about 1700ish rpm at 65mph. 1850ish rpm at 70mph. Gears and ratios are just fine for me. Allows for plenty of fun on the streets and can still knock down about 22 mpg on the highway if I really try.

Ferocity02

iTrader: (59)

Thanks guys. Probably going to go with 4.88's and a ValueTrac.

03regcab sierra

iTrader: (7)

My brother has the fbody t56 running 4.56s with a 305/35r20 its about 28.4" tall. He wants to go back ti 4.10s though