Duramax C10

[mackthehack]

I picked up 78 c10 a couple of days ago and already planning on doing an LBZ swap. I've got a couple of routes to go for the swap.

Keep the stock frame and box it, 9" rear end, dmax and 4l80 trans and all essential needs for the swap.

Or

Get a dmax single cab roller, chop the frame to a short bed length and do a chassis swap.

This thing is gonna be a dd and max power will be 600hp.

What do you guys recommend?

 

[SmokeShow]

Would you be leaving it 2wd if you chassis swap?


I'd lean towards using the modern chassis. BUT if staying 2wd, it might be difficult to keep the cab/bed low to the frame for clearances & that may make it a lil work to get a nice street stance on it.

So I guess if you go new chassis, I'd switch to 4wd. If wanting to stay 2wd, I'd prolly opt to stick with the current chassis.

 

[mackthehack]

Would you be leaving it 2wd if you chassis swap?


I'd lean towards using the modern chassis. BUT if staying 2wd, it might be difficult to keep the cab/bed low to the frame for clearances & that may make it a lil work to get a nice street stance on it.

So I guess if you go new chassis, I'd switch to 4wd. If wanting to stay 2wd, I'd prolly opt to stick with the current chassis.

I'm not set on keeping it 2wd. If I do a chassis swap, it'll be with 4wd chassis.

 

[03badmaxxx]

keep it 2wd and launch it like a boss

 

[WisconsinHick1]

When I find my mid to late 50's Chevy truck I will be keeping my modern frame because of my HP level I would be afraid of the frame twisting even if I boxed the frame. I also like my disk brakes.

 

[MD_Max]

Are the C10 front ends sufficient for the weight of the motor?

 

[OregonDMAX]

Did Brett keep the c10 frame on his 69. You would think the original frame even boxed and beefed up would still be lighter then a short bed dmax frame

 

[bcdeutsch731]

When I find my mid to late 50's Chevy truck I will be keeping my modern frame because of my HP level I would be afraid of the frame twisting even if I boxed the frame. I also like my disk brakes.

Not sure but I think I make pretty good power and i still have the stock frame. On my first frame i boxed it from the motor mounts to just behind the trans with 1/4" flat stock. On my second frame I boxed it from the motor mounts to the trans with 3/16 flat stock to save weight. On the first frame i used the stock suspension with big block front springs. On the second frame I welded in a Scott's Hot Rod front drop member with coil over front suspension. I have not had any problems with frame twist and i pull 1.3X 60ft and pull the front wheels about 6-8" off the ground. if your going to stay 2wd i would keep the old frame.
if your going to go 4x4 i would use a newer frame. My dad and I put a 72 blazer on an 06 frame with a d-max in it. It worked out great and we didn't have to modify the firewall at all like we had to do on my 69.

 

[WisconsinHick1]

I think the C10 frames look a little better built then the 50's frame.

 

[mackthehack]

Not sure but I think I make pretty good power and i still have the stock frame. On my first frame i boxed it from the motor mounts to just behind the trans with 1/4" flat stock. On my second frame I boxed it from the motor mounts to the trans with 3/16 flat stock to save weight. On the first frame i used the stock suspension with big block front springs. On the second frame I welded in a Scott's Hot Rod front drop member with coil over front suspension. I have not had any problems with frame twist and i pull 1.3X 60ft and pull the front wheels about 6-8" off the ground. if your going to stay 2wd i would keep the old frame.
if your going to go 4x4 i would use a newer frame. My dad and I put a 72 blazer on an 06 frame with a d-max in it. It worked out great and we didn't have to modify the firewall at all like we had to do on my 69.

Good info Brett, thanks. I think using the stock frame and boxing it will be the cheapest route to go. The truck already has a 10 bolt rear end. Do you think that will hold up to maybe 600hp and 1200+tq from a dmax? Or would a Ford 9" be a better route to go? I don't mind swapping to beefier axle shafts if either of those axle housing will hold up.

What trans would you recommend using? 4l80, a Ford trans, a Dodge trans or a th350?

 

[SmokeShow]

Def not a th350. Maybe a 400 but I'd rather have an OD trans for a street truck.

 

[OregonDMAX]

Def not a th350. Maybe a 400 but I'd rather have an OD trans for a street truck.

You can make a th400 plenty strong.

For a street truck you don't need OD I had a th400 in a daily driver 79 for almost 10 years and even drove across the country round trip. the OD is going to net you a little bit better mileage on the highway but its a street truck so if it was mine it would be city only.
If you have to have OD then go with the newer electronic GM transmissions

 

[weazel]

If you were to use a t400, with 3.08 gears, what would that net rpm wise approximately?

 

[bcdeutsch731]

Good info Brett, thanks. I think using the stock frame and boxing it will be the cheapest route to go. The truck already has a 10 bolt rear end. Do you think that will hold up to maybe 600hp and 1200+tq from a dmax? Or would a Ford 9" be a better route to go? I don't mind swapping to beefier axle shafts if either of those axle housing will hold up.

What trans would you recommend using? 4l80, a Ford trans, a Dodge trans or a th350?

If I were to keep my truck at 600hp I would put my Dana 61 back in the truck that has 3.00 gears in it with Mosier 5x4.75 axles with ford big bearing ends welded on. That rear end held up to 770rwhp and a 10.6 1/4 mile time.
As far as transmissions I would do a MikeL built Allison or go with a BTS 4r100. I think the Allison has come a long way from when I used it. My MikeL Allison was good to 9.8 1/4 mile. I just love the way the 4r100 shifted on the street. It was so quick and strong and shifted when it was supposed to.
I would NOT recommend a th400 for street only use. I run a 2.91 gear now and at highway speeds its not fun not having od.

 

[Turbo Performance]

If I were to keep my truck at 600hp I would put my Dana 61 back in the truck that has 3.00 gears in it with Mosier 5x4.75 axles with ford big bearing ends welded on. That rear end held up to 770rwhp and a 10.6 1/4 mile time.
As far as transmissions I would do a MikeL built Allison or go with a BTS 4r100. I think the Allison has come a long way from when I used it. My MikeL Allison was good to 9.8 1/4 mile. I just love the way the 4r100 shifted on the street. It was so quick and strong and shifted when it was supposed to.
I would NOT recommend a th400 for street only use. I run a 2.91 gear now and at highway speeds its not fun not having od.

I agree on not using a 400 in a street ride since it doesn't have an OD but there's no way I would put an Allison in a relatively light setup. Sure, they work great in most cases for a 3/4 ton truck but i wouldn't consider it a racing trans in really any other platform. Especially when you could get a 4l80e to live behind 600hp without a pile of money in it and without the added weight of the Allison. Bigger power like your truck might be a different story but even then I'd go th400 and gear vendors before the Allison if you had to have an OD.

 

[bcdeutsch731]

I do believe the 4l80 with a mild build would last at 600hp at a light weight. I just can't recommend one because I have never used one.

 

[Yellow Jacket]

Food for thought also is that Brad's truck has a roll cage... That helps with strength and twisting, but I don't see why everyone thinks the c10 frame won't hold up... I understand the diesel "torque", but I've seen 10 second cars on stock frames way smaller than a '79 c10, and cars with a partial cage run 8.50's and running 1.0x 60 ft times...

 

[Turbo Performance]

I do believe the 4l80 with a mild build would last at 600hp at a light weight. I just can't recommend one because I have never used one.

I can appreciate that. I ran a bone stock 4l80e last year at 400/800, 3500 lbs with zero issues. Even a stock converter. Lol. Changing setups to up the power this year so we'll see how well it lives. Everything I've read and everyone I've talked to seems to think a good input shaft and valve body is all you need in <800hp light weight cars.

Food for thought also is that Brad's truck has a roll cage... That helps with strength and twisting, but I don't see why everyone thinks the c10 frame won't hold up... I understand the diesel "torque", but I've seen 10 second cars on stock frames way smaller than a '79 c10, and cars with a partial cage run 8.50's and running 1.0x 60 ft times...

100% agree. I feel like the whole "diesel torque twisting frames" bit is blown out of proportion. At least in drag racing. There are plenty of street/rat rods, cars and trucks that have diesel swaps with good power, not lots of chassis underneath them, that don't have any issues. I really think you'd have to nail a big tire with a mile of power and a dinky chassis with no cage to have any discernible amount of twist. Bean's diesel has that 80's C10 with a cummins that damn near drags the bumper and twists up the front but it works and hasn't had problems from it. At some point you're just adding unnecessary weight.

 

[OregonDMAX]

I must be crazy to be running a th400 and 3.73's

 

[bcdeutsch731]

Food for thought also is that Brad's truck has a roll cage... That helps with strength and twisting, but I don't see why everyone thinks the c10 frame won't hold up... I understand the diesel "torque", but I've seen 10 second cars on stock frames way smaller than a '79 c10, and cars with a partial cage run 8.50's and running 1.0x 60 ft times...

I ran without a cage until I got into the 9's then I put a cage in it. I never had any problems with frame twist on my boxed frame 69 frame.

I can appreciate that. I ran a bone stock 4l80e last year at 400/800, 3500 lbs with zero issues. Even a stock converter. Lol. Changing setups to up the power this year so we'll see how well it lives. Everything I've read and everyone I've talked to seems to think a good input shaft and valve body is all you need in <800hp light weight cars.



100% agree. I feel like the whole "diesel torque twisting frames" bit is blown out of proportion. At least in drag racing. There are plenty of street/rat rods, cars and trucks that have diesel swaps with good power, not lots of chassis underneath them, that don't have any issues. I really think you'd have to nail a big tire with a mile of power and a dinky chassis with no cage to have any discernible amount of twist. Bean's diesel has that 80's C10 with a cummins that damn near drags the bumper and twists up the front but it works and hasn't had problems from it. At some point you're just adding unnecessary weight.

Bean's twisted there frame so bad the left front tire would not touch the ground.

I must be crazy to be running a th400 and 3.73's

Is it a diesel?