Ever done a T-56 swap onto a Gen I small block?

[matthew21lutz]

So, I currently have a th350 transmission and the gas mileage sucks, as most of you know. I'd like to get better mileage so, I was thinking of a t-56 transmission, has anyone else done it? What is everything I would need to do that? Trans, bellhousing, clutch, mounts, what else? What were your results if you've done it?

[74CustomK20]

Just a couple questions, but what's the intentions with the truck? Racing or high performance? Or just a DD wanting a little more range?

[Domer]

OK, depends on which transmission you get.. LT or LS based. I feel the LS is easier.. Cause i have an LT one.. Mine required custom flywheel(2 piece seal) if you have a newer one piece seal, you can use stock LT1 flywheel and clutch. The LT is a pull style clutch, so your limited on the clutch selection. Then hydraulics for the clutch. If you run a scatter shield, i believe they come with the option of setting up a regular clutch. then hardware, and the prices these days suck for T56.. Honestly, i did an American Power train swap in my buddies C10.. highly recommend. Versus my piece together that i am doing with a $500 Trans... The LS based requires a custom bell housing, and uses stock sbc parts for everything else. Hope this rambling makes sense. I have $960 into my clutch/flywheel combination for 650hp, and i havent even gotten to upgrading internals yet.. The hit up front for the full kit isnt as bad as it seems until you start piecing a t56 together. if you arent making alot of power, a t5 will last for awhile, or a TKO 5 speed will be cheaper and easier then a t56.

[matthew21lutz]

Originally Posted by 74CustomK20

Just a couple questions, but what's the intentions with the truck? Racing or high performance? Or just a DD wanting a little more range?

It's a daily driver, I drive on about 80 miles on a normal day, that's just to work and back.

[matthew21lutz]

Originally Posted by Domer

OK, depends on which transmission you get.. LT or LS based. I feel the LS is easier.. Cause i have an LT one.. Mine required custom flywheel(2 piece seal) if you have a newer one piece seal, you can use stock LT1 flywheel and clutch. The LT is a pull style clutch, so your limited on the clutch selection. Then hydraulics for the clutch. If you run a scatter shield, i believe they come with the option of setting up a regular clutch. then hardware, and the prices these days suck for T56.. Honestly, i did an American Power train swap in my buddies C10.. highly recommend. Versus my piece together that i am doing with a $500 Trans... The LS based requires a custom bell housing, and uses stock sbc parts for everything else. Hope this rambling makes sense. I have $960 into my clutch/flywheel combination for 650hp, and i havent even gotten to upgrading internals yet.. The hit up front for the full kit isnt as bad as it seems until you start piecing a t56 together. if you arent making alot of power, a t5 will last for awhile, or a TKO 5 speed will be cheaper and easier then a t56.

I thank you for all that information.. I understand some of it

Was looking into a brand new trans, I really don't wanna mess with anything used and having to rebuild it and everything. I know new is gonna cost a premium but, the reliability is worth it to me. http://www.summitracing.com/parts/awr-tuet11012 That,s what I'm looking into.

I have no idea as far as a what type of clutch, torque converter(I think manual trans have those) or anything besides the basics. I've driven standards but never extensively worked on any

[Domer]

For a daily driver, and wanting a new kit. This.
http://americanpowertrain.com/c-3205...ck-launch.html
Install kit for C10
http://americanpowertrain.com/c-1103...k-5-speed.html

[matthew21lutz]

Originally Posted by Domer

For a daily driver, and wanting a new kit. This.
http://americanpowertrain.com/c-3205...ck-launch.html
Install kit for C10
http://americanpowertrain.com/c-1103...k-5-speed.html

So what would the cost difference be between having a t-56 and a tko? As far as the difference in work, I'm willing to put in the time and effort to get another gear and hopefully even better gas mileage.

[Domer]

Cost about more.. size is a big issue also. Depends if you have a high hump or lo hump.

[matthew21lutz]

Originally Posted by Domer

Cost about more.. size is a big issue also. Depends if you have a high hump or lo hump.

I'm alright with the cost honestly, I have the high hump that's removable as well.

[Domer]

One other thing, is your rear gear ratio and tire size. The one we did, he had 3.23 and 29" tires with a mild SBC and he couldn't use 6th gear. So you need to factor those in also..

[matthew21lutz]

Originally Posted by Domer

One other thing, is your rear gear ratio and tire size. The one we did, he had 3.23 and 29" tires with a mild SBC and he couldn't use 6th gear. So you need to factor those in also..

I've never gotten in the rear end, besides changing the gear oil, Never even looked at the rear gears. I'll look for that but, as far as tires, right now I have 33's

[andrewmp6]

Is your truck 2wd or 4x4?

[SCOTI]

Manual tranny's use clutches/pressure-plates; auto's use torque convertors.
A 700r4 would be the simplest way to get you that OD gearing (4spd auto).

If you want to swap to a manual just to have a manual trans, a 5spd would be better unless everything else in the drivetrain is set-up to utilize the 6th gear in a T-56. Heads, cam selection, intake, carb, gearing, & tire OD all will have an impact on mpg improvements vs. just swapping the trans (& not taking the other items into consideration).

[74CustomK20]

That's why I was curious as to use, a nv3500 is a much cheaper swap and also gains a 5th gear OD. Easy to find and cheaper. Just thoughts...

[Big Port Jimmy 6]

LS T-56 with the Adapter plate http://www.thegearbox.org/catalog/it...17/4803441.htm and a truck bell housing and pedals would be easy. Some type of front shifter also.

[SCOTI]

Still has a potentially useless gear if not packaged right.

[Domer]

an NV3500 would be an easy swap.. not super strong, but fine for a dd.

[matthew21lutz]

Originally Posted by andrewmp6

Is your truck 2wd or 4x4?

It's a two drive with, as of right now , a stock 305, th350, stock gears(I have no idea what gears) and 32" tires.

Originally Posted by SCOTI

Manual tranny's use clutches/pressure-plates; auto's use torque convertors.
A 700r4 would be the simplest way to get you that OD gearing (4spd auto).

If you want to swap to a manual just to have a manual trans, a 5spd would be better unless everything else in the drivetrain is set-up to utilize the 6th gear in a T-56. Heads, cam selection, intake, carb, gearing, & tire OD all will have an impact on mpg improvements vs. just swapping the trans (& not taking the other items into consideration).

I don't want a 700r4, the 5 and sixth gears is what I really want to be able to get the best millage as possible. As far as changing everything to go with it, that's why I'm asking, I need to know everything I'm going to need to make it absolutely perfect.

I've already got new intake and carb(Edelbrock Performer & 600cfm Carb) as the stock carb just flat out didn't work anymore and the intake was cracked. Was already thinking of either rebuilding the motor or getting a crate engine.

What would be the best to get it done right, as far as heads, cam, intake, carb, gears and od tire size? Again, I'm willing to spend the money and put the work in to get it done right, my step father will be helping me out, he's been a mechanic for 30 years now but, has never done a swap like this before.

Originally Posted by Domer

an NV3500 would be an easy swap.. not super strong, but fine for a dd.

It will be a daily driver but, this will be a work truck as well. I live on a ranch and pull 2500lbs to 8000lbs pretty regularly as well, so it needs to be strong.

[SCOTI]

Originally Posted by matthew21lutz

It's a two drive with, as of right now , a stock 305, th350, stock gears(I have no idea what gears) and 32" tires.

I don't want a 700r4, the 5 and sixth gears is what I really want to be able to get the best millage as possible. As far as changing everything to go with it, that's why I'm asking, I need to know everything I'm going to need to make it absolutely perfect.

I've already got new intake and carb(Edelbrock Performer & 600cfm Carb) as the stock carb just flat out didn't work anymore and the intake was cracked. Was already thinking of either rebuilding the motor or getting a crate engine.

What would be the best to get it done right, as far as heads, cam, intake, carb, gears and od tire size? Again, I'm willing to spend the money and put the work in to get it done right, my step father will be helping me out, he's been a mechanic for 30 years now but, has never done a swap like this before.

It will be a daily driver but, this will be a work truck as well. I live on a ranch and pull 2500lbs to 8000lbs pretty regularly as well, so it needs to be strong.

You seem to be fixated that the 6th gear will yield better mpgs. It possibly will, but how much actual improvement will you see and if you see it @ what cost? You really need to consider your return on investment.

I did a quick Google search for rpm calculators. A typical T-56 has a .50 6th gear. That ratio would yield about 1350rpm @ 70mph w/3.73's & your 32" tires. A carbed sbc/bbc is going to want 2000-2200rpm to be happy chugging down the road efficiently @ 70mph. Going up to 4.56's still has you under 1700rpm. There are optional aftermarket t-56's that offer different gear ratios (like a .67 6th gear) but the cost increases w/them.

Lower rpm does not mean automatic better mpg's. It will be quieter & there will be less wear on the motor but it's not a definite that mpg's will improve. They could actually get worse because the motor is lugging to push a brick down the roadway @ 70mph.

Yes, 6pds work great for late model fuel injected cars w/ much less frontal area & weight. But it's not likely that you'll get 2-3mpgs improvement over any other 5spd OD.

The motor needs to be efficient while being able to offer good torque production @ 2000-2200rpm. A 350 w/some GM Vortec (or similar) heads, a decent comp ratio, hyd roller cam spec'd to offer optimum torque @ the calculated rpm, dual plane intake, tuned carb, good ignition, a good 2.25-2.5" exhaust, & synthetic fluids front to rear will all help you.

You want the best mpg's? Here are good questions for you:

What kind of truck (year, type, etc...)?
What mpgs would you like to get w/the "ultimate' combo in your truck?
What is your current mpg average ("it sux" doesn't tell us much)?

[matthew21lutz]

Originally Posted by SCOTI

You seem to be fixated that the 6th gear will yield better mpgs. It possibly will, but how much actual improvement will you see and if you see it @ what cost? You really need to consider your return on investment.

I did a quick Google search for rpm calculators. A typical T-56 has a .50 6th gear. That ratio would yield about 1350rpm @ 70mph w/3.73's & your 32" tires. A carbed sbc/bbc is going to want 2000-2200rpm to be happy chugging down the road efficiently @ 70mph. Going up to 4.56's still has you under 1700rpm. There are optional aftermarket t-56's that offer different gear ratios (like a .67 6th gear) but the cost increases w/them.

Lower rpm does not mean automatic better mpg's. It will be quieter & there will be less wear on the motor but it's not a definite that mpg's will improve. They could actually get worse because the motor is lugging to push a brick down the roadway @ 70mph.

Yes, 6pds work great for late model fuel injected cars w/ much less frontal area & weight. But it's not likely that you'll get 2-3mpgs improvement over any other 5spd OD.

The motor needs to be efficient while being able to offer good torque production @ 2000-2200rpm. A 350 w/some GM Vortec (or similar) heads, a decent comp ratio, hyd roller cam spec'd to offer optimum torque @ the calculated rpm, dual plane intake, tuned carb, good ignition, a good 2.25-2.5" exhaust, & synthetic fluids front to rear will all help you.

You want the best mpg's? Here are good questions for you:

What kind of truck (year, type, etc...)?
What mpgs would you like to get w/the "ultimate' combo in your truck?
What is your current mpg average ("it sux" doesn't tell us much)?

Well I'm glad that I've asked, I had no idea that they needed to be at 2000-2200rpms to be happy. I know that american powertrain offers a close range t56 magnum that has a .62 as the 6th gear, same cost as a wide ratio with a .50 6th gear. I need to know what would be the best for the ride and gas mileage.

Honestly, "resale" value, i do not care about one bit, I'm never going to sell this truck, I do not like new cars and I like these old trucks. Do I want to spend an astronomical amount of money? No but, I'm okay with spending a good bit of money to have reliability, performance and good gas mileage. I'd like to go for road trips across the country at some point in this truck.

As far as your questions go, 83 c10 silverado.
I'd like to get upwards of 20-25 mpg, with a fuel injected small block chevy 305, maybe a 350. I like the reliability that the small blocks have, as well as the cost of parts. Currently I'm averaging about 8-11mpg on my truck. So on an average work week, driving 80 miles a day and maybe 20 miles on the weekends, I'm spending right at $500 a month in gas. Mind you gas is not getting cheaper than $2 a gallon lol it's been going up more n more lately so, this brings concern for me. I can't afford to be driving it like this if gas hits $5 a gallon like it nearly did a few years ago.

[Big Port Jimmy 6]

Originally Posted by SCOTI

Still has a potentially useless gear if not packaged right.

Indeed had a 57 vert in the shop with a fastburn 385, t56 and 3:23 gears. You didn't need 6th till 115ish. I wanted to put in 4:56 but made do with 3:89s 6th around 70.
It has to be a whole package. Jay

[matthew21lutz]

Originally Posted by Big Port Jimmy 6

Indeed had a 57 vert in the shop with a fastburn 385, t56 and 3:23 gears. You didn't need 6th till 115ish. I wanted to put in 4:56 but made do with 3:89s 6th around 70.
It has to be a whole package. Jay

Well I'm glad this forum exists and that y'all are here to help! I really appreciate y'alls advice.

[SCOTI]

Originally Posted by matthew21lutz

Well I'm glad that I've asked, I had no idea that they needed to be at 2000-2200rpms to be happy. I know that american powertrain offers a close range t56 magnum that has a .62 as the 6th gear, same cost as a wide ratio with a .50 6th gear. I need to know what would be the best for the ride and gas mileage.

Honestly, "resale" value, i do not care about one bit, I'm never going to sell this truck, I do not like new cars and I like these old trucks. Do I want to spend an astronomical amount of money? No but, I'm okay with spending a good bit of money to have reliability, performance and good gas mileage. I'd like to go for road trips across the country at some point in this truck.

As far as your questions go, 83 c10 silverado.
I'd like to get upwards of 20-25 mpg, with a fuel injected small block chevy 305, maybe a 350. I like the reliability that the small blocks have, as well as the cost of parts. Currently I'm averaging about 8-11mpg on my truck. So on an average work week, driving 80 miles a day and maybe 20 miles on the weekends, I'm spending right at $500 a month in gas. Mind you gas is not getting cheaper than $2 a gallon lol it's been going up more n more lately so, this brings concern for me. I can't afford to be driving it like this if gas hits $5 a gallon like it nearly did a few years ago.

You need to consider an LS based drivetrain for those numbers. I don't think you'll get there w/the old school power plants despite their reliability (even w/lots of tuning). Even then..... Aerodynamics will hinder the goal. My buddies more fluid 2000 GM truck (single cab short-fleet) yielded about 23mpg on the highway w/the LS based 5.3/4l60e combo. With tuning you might reach a similar number in a square but an LS power plant is more efficient vs a sbc.

[matthew21lutz]

Originally Posted by SCOTI

You need to consider an LS based drivetrain for those numbers. I don't think you'll get there w/the old school power plants despite their reliability (even w/lots of tuning). Even then..... Aerodynamics will hinder the goal. My buddies more fluid 2000 GM truck (single cab short-fleet) yielded about 23mpg on the highway w/the LS based 5.3/4l60e combo. With tuning you might reach a similar number in a square but an LS power plant is more efficient vs a sbc.

Well I might just have to keep the small block and change it to a five speed. Then get an older camaro, monte carlo or something along those lines and put an ls in it.

I really appreciate all of your help and knowledge, I would've gone and done all this only to find out that it doesn't work.