Gears for a T56?

[kSStamp0182]

Originally Posted by GCncsuHD

26.7 tires and the lower .57 6th gear....

Even with 5.13s and that 30" tire he will be looking at only 2000 rpm at 70 in 6th gear, that is pretty ideal for fuel mileage, also consider that your V was not a flying brick, and did not need to overcome the drag nearly as much as one of these trucks would.

Considering a stock 3speed would be looking at 3100rpm at 70mph with the stock 3.73s and a 30" tire, I think the 5.13s with the t56 would be great at 2000rpm at 70.

agreed. and again the CTS-V is a higher torque LS6 vs the LS1

[GCncsuHD]

Originally Posted by kSStamp0182

agreed. and again the CTS-V is a higher torque LS6 vs the LS1

Yep, unless it was the even more powerful LS2

[Custom 68]

Rob that is looking good, could you grab me a measurement on your engine placement? Just something simple like from the radiator to the passenger side head or something to be consistant. I built my own mounts years ago and am looking at the placement of the shifter, I am afraid it will be too far back on mine, your inside photo shows the placement in relationship to the stiffener rib. Anyway when you have a chance if you could. I will be swaping mine out before long, i also have a 6.0 if necessary, i have been collecting for a while. These things do see to have a fair amount of torque even my little 5.3.

[Ackattack]

I had 2 firebirds and a corvette all with LS1 powered T56 trannies. They all had stock 3.42 gears and I used 6th gear (.50 ratio) from about 45-50 on up. This was just cruising around and it worked fine.

I'd go with 4.10s for a good comprimise.

[Hart_Rod]

Guys thanks for all the good info and suggestions. Obviously everyone has different driving styles and preferences. Since the truck has 3.73s already, I'll probably add a posi and drive it for a while to see how I like it and then go from there.

Originally Posted by Custom 68

Rob that is looking good, could you grab me a measurement on your engine placement? Just something simple like from the radiator to the passenger side head or something to be consistant. I built my own mounts years ago and am looking at the placement of the shifter, I am afraid it will be too far back on mine, your inside photo shows the placement in relationship to the stiffener rib. Anyway when you have a chance if you could. I will be swaping mine out before long, i also have a 6.0 if necessary, i have been collecting for a while. These things do see to have a fair amount of torque even my little 5.3.

This setup has the ECE motor mounts and it moves the engine forward more than some of the other setups. From the back of the passenger's side head to the firewall is approximately 4". Let me know if you need more measurements.

[Custom 68]

nope Rob that will give me a reference dimension. just wanted to see where my shifter would be, i think i may have to move it forward.

[Hart_Rod]

Originally Posted by Custom 68

nope Rob that will give me a reference dimension. just wanted to see where my shifter would be, i think i may have to move it forward.

They make a kit that will move the shifter location to the forward access plate, but it's not cheap....

[TR65]

I moved my T56 shifter forward using the Keisler kit. The stock shifter comes up under the seat if you want to use the original bench. Here is a thread on the modification. It is a bear but mine works well in the end.

http://67-72chevytrucks.com/vboard/s...d.php?t=300892

TR

[Custom 68]

Thanks tr yes I had followed ur thread and have it saved. I may attempt it myself like u did. I sat my motor as far back as possible so yes I will have some interferance. my auto sure works good now. we will see on what I do.
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[Chevrolet4x4s]

And with 3.07s 349mph Bonneville anyone
Shane

[chapster]

Just thought I would chime in,

I had trouble with this decision also. For my LS2 I ended up going with 4:10's with a 29" tire, 4L65e (1rst:3.06, 2nd:1.63, 3rd:1.00 4rth:.070), 3200 stall

I am now struggling with cam specs with this set-up. I would recommend determining that at the same time.

I was after a real lumpy cam but the weight of the truck also becomes a factor. With that being said, how much does 300lbs make??

[kSStamp0182]

well with the t56 it wont matter really. the cam wont effect it like it does a auto, will affect drivability tho

[Hart_Rod]

Originally Posted by Custom 68

Rob that is looking good, could you grab me a measurement on your engine placement? Just something simple like from the radiator to the passenger side head or something to be consistant. I built my own mounts years ago and am looking at the placement of the shifter, I am afraid it will be too far back on mine, your inside photo shows the placement in relationship to the stiffener rib. Anyway when you have a chance if you could. I will be swaping mine out before long, i also have a 6.0 if necessary, i have been collecting for a while. These things do see to have a fair amount of torque even my little 5.3.

Here's some more pictures of the positioning...

[dznucks]

Rob, how is this project coming along?

I am about to install a T-56 and was wandering how the gear situation worked out with this truck.

That looks alot like Shifty's old truck. I know he sold it, but didnt know to who. If it is, I have the original steering wheel.....if you are interested.

[Hart_Rod]

Originally Posted by dznucks

Rob, how is this project coming along?

I am about to install a T-56 and was wandering how the gear situation worked out with this truck.

That looks alot like Shifty's old truck. I know he sold it, but didnt know to who. If it is, I have the original steering wheel.....if you are interested.

It is Shifty's old truck, I bought it for my son. No real progress yet, other than gathering some parts... I will probably go with 4.11's or 3.73's, just depends on the tire size we go with. I 'll have more to follow when we get to that point. What kinda shape is the wheel in? Any pictures?

[nibs]

Watching this as well...

[OJ1988]

The problem with running ,4.56 or 4.88 or 5.13s is you will rev so quick you will have to shift through the first 3 gears real quick.

These 6 speeds are great, but a comprimise has to be made.

Most the guyson pro-touring.com that run these in there cars with a 28" tire run 3.73 or 4.10's and most will say 6th gear is not used much at all, but the the rear gear works well with the first 4 gears of the trans.

[Hart_Rod]

Originally Posted by OJ1988

The problem with running ,4.56 or 4.88 or 5.13s is you will rev so quick you will have to shift through the first 3 gears real quick.

These 6 speeds are great, but a comprimise has to be made.

Most the guyson pro-touring.com that run these in there cars with a 28" tire run 3.73 or 4.10's and most will say 6th gear is not used much at all, but the the rear gear works well with the first 4 gears of the trans.

Good info, thanks!
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[Green 1959]

Here is a crazy question, I have read what everyone has thought find it all very interesting. Is there anyone running a old V8 or inline 6 with this trans? I have a thing for L6's and thought it might be cool to have a 67-72 Suburban with a 250 and a t56 and a 3.73 or 4.11 rear end. The reason I would like to go with this would be it would be a simple power train (at least at the dream stage) that would get decent fuel mileage for long trips. I don't expect to anything over 20 but one can hope. Another question I have is it true that you have to use a hydralic clutch?

[theastronaut]

Originally Posted by Green 1959

Here is a crazy question, I have read what everyone has thought find it all very interesting. Is there anyone running a old V8 or inline 6 with this trans? I have a thing for L6's and thought it might be cool to have a 67-72 Suburban with a 250 and a t56 and a 3.73 or 4.11 rear end. The reason I would like to go with this would be it would be a simple power train (at least at the dream stage) that would get decent fuel mileage for long trips. I don't expect to anything over 20 but one can hope. Another question I have is it true that you have to use a hydralic clutch?

I almost built a 250/ LT1 T56 combo for my '66 C10. I think there are adapters that let you run your original bellhousing and clutch arm? Not 100% sure about that. An LT1 bellhousing will bolt right up to a small block or inline 6. With a 4.56 R&P and 29" tall tires, 75 mph equals 2000 rpm. A 3.73 or 4.11 would drop the engine out of its powerband at highway speeds unless you dropped down to 5th gear.

[Green 1959]

YES!!! That is the direction I want to go.