Diesel in a '70 C-30

[77GMCSerria]

I am thiking about puting a diesel in a 70 C-30 350 4 speed to pull a 5th wheel camper. I was thinking to go with either a Cummins 6bt or 4bt with a RTO-6610 or a Detroit Diesel with the RTO-6610. I want a manual transmission. I have looked around and it seems like most people are using Cummins. Any ideas on what would be a good swap?

[Wrenchbender Ret]

I wouldn,t use the 4BT. It is sluggish, vibrates & is noisey. The GM 6.2-6.5 are a bolt-in but unless you Turbo charge it they are a little sluggish.

[77GMCSerria]

Can you bolt the RTO6610 to a 6.2 or 6.5? I would want to turbo it tho thats why I was thinking Cummins or Detroit Diesel.

[1969 GMC]

Do you happen to have that transmission already? If not, or you don't have one lined up, good luck getting one cheap. Most tranny rebuild places can get you one, but you need a core...and it will be expensive anyway.

I would just try to find a Dodge Ram with the NV4500 or NV5600 and just swap the entire drivetrain (including rearend) to your truck. I am sure motor mounts wouldn't be that big of a problem.
You could also do the same thing with a 6.5, just find a donor truck.

I think that with any of the small Detroits (well, small enough to fit inside a 1 ton truck), the 4bt, or the 6.2, you will find it lacking in power to tow.

[68MoneyPit]

I'd rather be Cummin than Strokin, so stay away from a PowerJoke and who really wants a chevy diesel anyways. Run the Cummins 5.9 and get a power programmer. I have a 2001 Dodge with an Edge Pro Comp programmer and it is a workhorse and will lay all the rubber you want to part with. Tires do get a little expensive though.

[72freak]

There are about 6000 posts about this very thing here on this site. Check the archives.

Some like GM
Some do the Cummins

I prefer the Cummins and have plans for a 4TB in the near future.

[1tons4life]

Originally Posted by 68MoneyPit

I'd rather be Cummin than Strokin, so stay away from a PowerJoke and who really wants a chevy diesel anyways. Run the Cummins 5.9 and get a power programmer. I have a 2001 Dodge with an Edge Pro Comp programmer and it is a workhorse and will lay all the rubber you want to part with. Tires do get a little expensive though.

The powerstoke as to much computer to run with out rewire the truck. the best way is to run the old 12 valve cummins there turbo and no computer everything is mech. the newwer uoy get the more computer stuff there is try to stay with older ones. you can also get a old 7.3 non turbo or 6.2 6.5 same way and then upgrade and add a turbo theres no cumputer to control the turbo that why. or get all the computer parts for a newwer one and wire it up to your truck it takes alot of time but the newwer diesel have more power. my 67 is going to get 01 7.3 powerstroke in feb with 650hp 1200ft. and a 6speed man.

[77GMCSerria]

I think that a Cummins is the motor to go with but the transmission is still up in the air.

The 70 GMC has a daully rear end so if I were to find a doner truck I would need to get a dually doner.

[68MoneyPit]

Just find a totalled out Dodge dually in the junkyard and take the whole drivetrain. Then all you have to do is have the driveshaft cut to length. If you are going with an auto you may want to have the transmission gone through and put in a shift kit. That is the weak point. Good luck Jyard diving.

[77GMCSerria]

I do want a manual preferably a 6 speed.

[70 Suburban]

I have an old IH 7.3 sittin in the back yard.9in the van still) I have thought about using it.. not sure just yet

[77GMCSerria]

Just a thought, I found a wrecked 2002 Chevy Dump Duramax w/ 62k miles for $11,000.00. Has anyone put a Duramax in a 70's truck?

What would be easier Cummins or Duramax?

I know the Duramax has a lot of wiring but if you have a full parts truck, that should make it easier.

[1tons4life]

theres alot of wires to it but the benifets are great a older cummins is easier but does not have the power or the upgrades.

[77GMCSerria]

What manual transmissions bolt up to the Duramax?

I guess I could just drop the 70 GMC cab on the 2002 Chevy's chassis if the frame is good.

[1tons4life]

im not sure which it is but i would look it to another one anyways the 6 speed that goes behide it suck the clutch is #### and the trans is hard to find do to chevy will not put it in anything other there the stripped base models anything above a base and its a auto. look in to ford or dodges 6 speeds or the old deisel 5 sppeds I dont now if it will work but chevy 6 speed is not worth the trouble.

[77GMCSerria]

I think I'll just stick with the Cummins.

[1tons4life]

its easier thats the way i would go

[77GMCSerria]

For the transmission I was going to go with either a Eaton or NV5600 or the ford ZF6 (6 speed).

[1tons4life]

Originally Posted by 77GMCSerria

For the transmission I was going to go with either a Eaton or NV5600 or the ford ZF6 (6 speed).

ZF6 if its the trans from the diesel its a great trans it has alot of hd clutch upgrades and a nice granny gear an the low and revs are both on the drivers side so its just like shifting a 5 speed when you dont use low.

r 1 3 5
l 2 4

[77GMCSerria]

If I use the ZF6 from a diesel what clutch and flywheel would I use?

[woodchip]

Just put you a 396 or 454 Gas engine in it, with a 400 trans and pull what ever you want to. Besides Gas is cheaper than Diesel .My 68 C10 has a 396 with 400 and I have carried and pulled anything I wanted to with it.

[77GMCSerria]

I want a Diesel, even tho gas is cheaper than diesel you get more miles per gallon with diesel.

[67_C-30]

Originally Posted by 77GMCSerria

I want a Diesel, even tho gas is cheaper than diesel you get more miles per gallon with diesel.

Many more miles to the gallon. It's not uncommon with 6.2/6.5's to get 20-22 MPG in a dually, where a big block will get 10 on a good day. I have an '84 K1500 with a 6.2 that gets about 27 on the highway with the 700R4 tranny.

BTW, here's a 10-second '70 C-10 with a Duramax!
http://www.dieselpowermag.com/featur...max/index.html

[77GMCSerria]

The only reason I was thinking about using a Duramax was that there is a 2002 Chevy Dually Dump with a Duramax w/ 62k miles at a local junk yard. He wants $11,000.00 for it. But I want a manual transmission, I don't know of any manual transmissions that came mated to a Duramax.

[JAKES 68GMC]

This is the first time I've ever seen anyone call a 4bt cummins sluggish. 275lb. ft of torque is sluggish for a 239cu. in 4 cylinder? and thats stock, you can juice them up more than that.