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.

[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.

[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.

[67_C-30]

Originally Posted by 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.

In stock form they actually are pretty sluggish. Sure that's pretty impressive for a 239 cu in 4 cyl, but its still a 239 cu in 4 cyl. When turbo charged, and the IP turned up they run pretty good, but are real brash and they vibrate a lot no matter what you do to them. The 5.9 is a lot more pickup truck friendly.

[sodak69c10]

go with the DURAMAX then you can say it is all GM, the cummins are good to ,

[special-K]

www.peninsularmarine.com
I run the 300hp and love it.Runs great and surprises all the $45,000 newbies.Bolt-in ease into a 67/72.

[77GMCSerria]

I have thought about using the 4bt but, it seems like it is more expensive to buy than the 6bt, plus you get more power from the 6bt.

[1969 GMC]

Originally Posted by 77GMCSerria

I have thought about using the 4bt but, it seems like it is more expensive to buy than the 6bt, plus you get more power from the 6bt.

Like anything else, look around. The high school I went to had an old Frito Lay P30 delivery van that was used to take the marching band instruments to football games and competitions. A year or two after I graduated, they held a sealed bid auction and someone got it for $900!

It had a 4bt/SM465, not to mention the body is all aluminum...can we say high scrap prices? I believe the guy basically paid for the purchase price through scrapping the body out, and had a free drivetrain.

Also, a lot of the mods that can be done to 6bt's can be done to the 4, since they are basically the same engine minus two cylinders.

As far as power goes, that old van seemed to be on par with or slightly below (only slightly) than the 350 that was in my GMC when I bought it, not talking #'s but sheer seat of the pants feel.

[BCOWANWHEELS]

A 4 BT HAS MORE TORQUE THAN A 350 CHEVY AND FITS PERFECT. a 6 bt also fits perfect. i,am doing a 6 bt in my 1972 c-30 and a 4bt in my c-10 1971. the 4bt will get 25+ mpg and the 6bt with 3.21 gears will get 20+ mpg. those 6.2,s & 6.5,s are problem prone engines ( bottom end of block cracks real bad )
bob

[77GMCSerria]

I wouldn't use the 6.2 or 6.5, I have heard a lot about the cummins being a better engine.

[67_C-30]

Originally Posted by BCOWANWHEELS

A 4 BT HAS MORE TORQUE THAN A 350 CHEVY AND FITS PERFECT. a 6 bt also fits perfect. i,am doing a 6 bt in my 1972 c-30 and a 4bt in my c-10 1971. the 4bt will get 25+ mpg and the 6bt with 3.21 gears will get 20+ mpg. those 6.2,s & 6.5,s are problem prone engines ( bottom end of block cracks real bad )
bob

Although I would agree handily that the Cummins is the better engine, I gotta say I have had 3 trucks with 6.2/6.5's and they have been rock solid except the glow plug controllers. I've found if you put a manual glowplug switch on them, they'll crank with ease and run forever. I have a '84 K1500 with 321,000 miles on it, a '83 3/4 ton Suburban with 203,000 miles, and I recently sold a '93 C3500 service body truck with 261,000 miles on them. I a low mileage 6.5 TD out of wrecked C2500 that I am going to put in my '67 C-30. Everyone has their preferences, but I am not scared of these engines, and they get great fuel mileage. My beat up, worn out K1500 (6.2 - 700R4 3.40's) has got as good as 27 mpg on the highway. The Burb gets around 20mpg with a TH400 and 3.73's.

[68K20 x Drill]

4BT in C10
http://www.youtube.com/watch?v=jRvtPl_6gc8&feature=user

[77GMCSerria]

I know that it can be done. I was wondering if anyone has any pics of there swap of a 6bt or 4bt or Duramax in to a 67-70 GM truck?

[bighoss0331]

extend the frame beef it up and put a CAT in it