Suggestions on transmission - The 1947 - Present Chevrolet & GMC Truck Message Board Network

bazkook · 10-01-2006, 11:11 PM

I am about to start fixing up my 70 C10 with a inline 6 and three speed on the column. I'm going to ditch the I-6 for a 383 stroker and I want the truck to be for the street and strip. I'm torn between the transmission I want. The mechanic who is going to work on the truck keeps suggesting a 350 trans with shift kit because it would be the cheapest and most reliable but I really want overdrive to get some decent gas mileage. I also want to the transmission to be able to hold up to about about 600 horses or so. The 383 I'm building will have close to that or more on a 125 shot of nitrous. I'm would really like to spend no more than $2000 on the transmission if that's possible for this truck. Any suggestions would be greatly appreciated.

Longhorn Man · 10-01-2006, 11:29 PM

600 horses?
I'd go with a TH400, and go with a good freeway gear. A good 383 will have the torque you need to take off with that gear, and you'll be cruising at decent RPMs... and no worrys of a weak ass overdrive falling apart.
For 2 grand, you'll never get an overdrive to hold up to that kind of power... not for long anyways.

*trkklr77* · 10-01-2006, 11:40 PM

x2

hp and trq need a th400.

junkyardjohn · 10-02-2006, 12:23 AM

Yep... No Doubt About It. A T-400 With A Gear Vendor Overdrive Behind It. Your Going To Spend A Little More Than 2 Grand, But It's Pretty Close To A Bullet Proof Setup.

John

Werewolf · 10-02-2006, 03:04 AM

No stock GM overdrive trans will hold that, period. Even B&M says their performance 700's will only hold into the 400 range on torque.

bazkook · 10-02-2006, 08:42 AM

What gears would be suitable? 3.55s or higher? The truck has 3.73s now.

**N2TRUX** · 10-02-2006, 08:52 AM

Quote:

Originally Posted by bazkook

What gears would be suitable? 3.55s or higher? The truck has 3.73s now.

That depends on how tall a tire you plan to run. Regardless of the transmission/rear gear I don't see the ability "to get some decent gas mileage" with a 475 horse motor.

bazkook · 10-02-2006, 09:07 AM

Quote:

Originally Posted by N2TRUX

That depends on how tall a tire you plan to run. Regardless of the transmission/rear gear I don't see the ability "to get some decent gas mileage" with a 475 horse motor.

I don't know what size tire I'm going to run yet. I'd have to get back to you on that. I know I'm going to get some slicks from a guy but I don't know their size. I know you can't get decent gas mileage with a motor like this but I'd like to aim for mid 10s. Suppose I went over the $2000 mark. What kind of overdrive trans could I get that could handle the power I'm making?

watahyahknow · 10-02-2006, 09:11 AM

on the turbo 400 the E80 overdrive box might be built strong enough but you be spending more cash on all the hardwhare around the box to get it to work prolly for less money and trouble i rather go for the 400 with gear vendor overdrive

bazkook · 10-02-2006, 09:22 AM

Quote:

Originally Posted by watahyahknow

on the turbo 400 the E80 overdrive box might be built strong enough but you be spending more cash on all the hardwhare around the box to get it to work prolly for less money and trouble i rather go for the 400 with gear vendor overdrive

What part of the above post did you agree on?
Where can you get gear vendor overdrive? About how much money would that cost?

**N2TRUX** · 10-02-2006, 09:29 AM

Quote:

Originally Posted by bazkook;

....Where can you get gear vendor overdrive? About how much money would that cost?

GVOD

bazkook · 10-02-2006, 09:37 AM

Man $2400! I probably would be better off going with a TH400 with higher gears.

Werewolf · 10-02-2006, 04:49 PM

Yeah, that's generally how it works. I've been spending some time thinking about how I should set up the drivetrain on my truck. It's got a stock 3.08 posi, which is bound not to work anymore, anyway, but it's a decent gear for a big block. I'd love the first gear and overdrive of a 700, but a 400 is a better bet behind a big block. Of course, now I have this crazy notion of using an Allison automatic from a 8.1L powered newer Silverado, or a T-56 manual trans.

And my '95 Trans Am (390-ish at the fly) gets 25mpg.

Longhorn Man · 10-02-2006, 04:52 PM

You are trying to get the best of both worlds, and it isn't cheap to do.
You want to launch outta the hole hard enough that the tailgate wants to fall off, yet, you want to go down the freeway at a step over idle. (I'm obviously exadurating on both ends) It can be done, but it won't be cheap.
The gear vendors is a tough unit. You will never break it.
As for GM auto/overdrives, there are a few options;
200 4R ... you'll kill it in no time with a $2k budget
700R4 ... It'll probably last a tad bit longer than the 200 4R... but not by much with the $2k Budget
4L6E ... Same as the 700 R4, but much more expensive to set up.
4L80E ... may hold up for quite a while, but you probably won't be able to do it for the price cap.

The 4L80E would be very expensive to aquire, and to rebuild. Plus, on top of all that, you'll need a computer to controll it. There are aftermarket stand alone computers with the sensors and stuff you'll need, but it'll make you cry if you price it. There is also a one year only, that GM used this tranny in 6.5 liter trucks, where it has a factory stand alone computer. I want to say it was like 92 ... maybe 93. IF... and that is a huge if, you can locate one and get the whole harness and computer and all sensors it is hooked to, esp if you see this in a junk yard... then, you may be able to do the 4L80E for less than 3K. This includes getting the tranny, having it rebuilt by a good shop, a new converter, and you installing it.
Don't forget the drive shaft mods you'll need to do...that goes for any OD tranny you go with.

This is why I mentioned getting a good freeway gear, and aim for gobs of low end torque. There's guys with the cad 500 big blocks, that run 2.73 gears on the strip and running absurd times... like 12's in full size vehicles... and turning 1800 RPM on the freeway with a TH400.

10-01-2006, 11:11 PM	#1
bazkook Registered User Join Date: Jul 2006 Location: Georgia Posts: 42	Suggestions on transmission I am about to start fixing up my 70 C10 with a inline 6 and three speed on the column. I'm going to ditch the I-6 for a 383 stroker and I want the truck to be for the street and strip. I'm torn between the transmission I want. The mechanic who is going to work on the truck keeps suggesting a 350 trans with shift kit because it would be the cheapest and most reliable but I really want overdrive to get some decent gas mileage. I also want to the transmission to be able to hold up to about about 600 horses or so. The 383 I'm building will have close to that or more on a 125 shot of nitrous. I'm would really like to spend no more than $2000 on the transmission if that's possible for this truck. Any suggestions would be greatly appreciated. Last edited by bazkook; 10-01-2006 at 11:13 PM.

10-01-2006, 11:29 PM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: Suggestions on transmission 600 horses? I'd go with a TH400, and go with a good freeway gear. A good 383 will have the torque you need to take off with that gear, and you'll be cruising at decent RPMs... and no worrys of a weak ass overdrive falling apart. For 2 grand, you'll never get an overdrive to hold up to that kind of power... not for long anyways.

10-01-2006, 11:40 PM	#3
trkklr77 Account Suspended Join Date: Aug 2006 Location: vacaville ca, because it as far from indy as i can be Posts: 775	Re: Suggestions on transmission x2 hp and trq need a th400.

10-02-2006, 12:23 AM	#4
junkyardjohn Registered User Join Date: Aug 2001 Location: SOMERSET KY. Posts: 6,425	Re: Suggestions on transmission Yep... No Doubt About It. A T-400 With A Gear Vendor Overdrive Behind It. Your Going To Spend A Little More Than 2 Grand, But It's Pretty Close To A Bullet Proof Setup. John __________________ junkyardjohn 69 1 TON TOW TRUCK // 84 4WD CUCV BLAZER// 85 1 TON 4WD STAKE TRUCK// 86 M1031 5/4 TON 4WD CUCV// ALOT OF OLD TRUCKS FOR ONE OLD MAN TO DRIVE. THERES ROOM FOR ALL OF GODS CREATURES RIGHT NEXT TO MY MASHED POTATOES// LIFE MEMBER OF P.E.T.A (PEOPLE EATING TASTY ANIMALS) DON'T RENT U-HAUL ALWAYS TELL THE TRUTH IT WILL AMAZE PART OF THE PEOPLE & ASTONISH THE REST

10-02-2006, 03:04 AM	#5
Werewolf Woof? Join Date: Jun 2005 Location: Raleigh, NC Posts: 276	Re: Suggestions on transmission No stock GM overdrive trans will hold that, period. Even B&M says their performance 700's will only hold into the 400 range on torque. __________________ 1968 LWB CST BB 2004 Avalanche Z71 LT3. 2003 S-10 ZR2 (hers). 1997 Astro 1992 Caprice wagon, 500k stock miles. Nursing wounds after a bad wreck. 1997 Saturn - need gas mileage from something!

10-02-2006, 08:42 AM	#6
bazkook Registered User Join Date: Jul 2006 Location: Georgia Posts: 42	Re: Suggestions on transmission What gears would be suitable? 3.55s or higher? The truck has 3.73s now.

10-02-2006, 09:11 AM	#9
watahyahknow Registered User Join Date: Jul 2006 Location: the netherlands europe Posts: 4,335	Re: Suggestions on transmission on the turbo 400 the E80 overdrive box might be built strong enough but you be spending more cash on all the hardwhare around the box to get it to work prolly for less money and trouble i rather go for the 400 with gear vendor overdrive __________________ i got a job again and having fun at it too idea's for the trucks and the order of things to do are taking shape and get closer to being realized , a few more months and i be able to start building for real i complete 2 of the trucks intoo running fashion one custom and one basicly stock the thirth will be sacrificed for parts

10-02-2006, 09:37 AM	#12
bazkook Registered User Join Date: Jul 2006 Location: Georgia Posts: 42	Re: Suggestions on transmission Man $2400! I probably would be better off going with a TH400 with higher gears.

10-02-2006, 04:49 PM	#13
Werewolf Woof? Join Date: Jun 2005 Location: Raleigh, NC Posts: 276	Re: Suggestions on transmission Yeah, that's generally how it works. I've been spending some time thinking about how I should set up the drivetrain on my truck. It's got a stock 3.08 posi, which is bound not to work anymore, anyway, but it's a decent gear for a big block. I'd love the first gear and overdrive of a 700, but a 400 is a better bet behind a big block. Of course, now I have this crazy notion of using an Allison automatic from a 8.1L powered newer Silverado, or a T-56 manual trans. And my '95 Trans Am (390-ish at the fly) gets 25mpg. __________________ 1968 LWB CST BB 2004 Avalanche Z71 LT3. 2003 S-10 ZR2 (hers). 1997 Astro 1992 Caprice wagon, 500k stock miles. Nursing wounds after a bad wreck. 1997 Saturn - need gas mileage from something!

10-02-2006, 04:52 PM	#14
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: Suggestions on transmission You are trying to get the best of both worlds, and it isn't cheap to do. You want to launch outta the hole hard enough that the tailgate wants to fall off, yet, you want to go down the freeway at a step over idle. (I'm obviously exadurating on both ends) It can be done, but it won't be cheap. The gear vendors is a tough unit. You will never break it. As for GM auto/overdrives, there are a few options; 200 4R ... you'll kill it in no time with a $2k budget 700R4 ... It'll probably last a tad bit longer than the 200 4R... but not by much with the $2k Budget 4L6E ... Same as the 700 R4, but much more expensive to set up. 4L80E ... may hold up for quite a while, but you probably won't be able to do it for the price cap. The 4L80E would be very expensive to aquire, and to rebuild. Plus, on top of all that, you'll need a computer to controll it. There are aftermarket stand alone computers with the sensors and stuff you'll need, but it'll make you cry if you price it. There is also a one year only, that GM used this tranny in 6.5 liter trucks, where it has a factory stand alone computer. I want to say it was like 92 ... maybe 93. IF... and that is a huge if, you can locate one and get the whole harness and computer and all sensors it is hooked to, esp if you see this in a junk yard... then, you may be able to do the 4L80E for less than 3K. This includes getting the tranny, having it rebuilt by a good shop, a new converter, and you installing it. Don't forget the drive shaft mods you'll need to do...that goes for any OD tranny you go with. This is why I mentioned getting a good freeway gear, and aim for gobs of low end torque. There's guys with the cad 500 big blocks, that run 2.73 gears on the strip and running absurd times... like 12's in full size vehicles... and turning 1800 RPM on the freeway with a TH400.



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