Drivetrain for 84 c30 crewcab dually

[The Donchy Vetah]

Hi, new to the site. I just bought an 85 crewcab 1 ton dually with no engine or trans and I wanted to know if a chevy inline 6 will drop in to this with out mods.  My next question is what in you guys opinion is the best setup for towing and longevity? My ultimate goal is to drop a cadillac big block in.

Thanks for any input

[LTZ C20]

Welcome from central California. For a 1 ton dually, at minimum a healthy small block is what I would use, but with that kind of towing ability I always lean to a diesel, if that is too expensive then a healthy big block.

[The Donchy Vetah]

Thanks for the welcome.

Yes the diesel route would be a stretch unless maybe i went junkyard shopping. Ok then, how about manual trans vs. Auto? (Originally an automatic)

[LTZ C20]

Junk yard can actually be fairly cheep, I think we had a member here get a complete truck from a junk yard the the Duramax diesel engine and Allison transmission, I think he got it for under 1000 dollars cuz the truck had been wrecked, he pulled all the parts off the donor he needed.

As for trans, if it came with an auto, I would stay with an auto. Switching to manual requires some things to be re-worked and adjustments made to fit the required parts but if you prefer manual then go for it. In reality, it's all personal preference, I've driven diesel trucks with auto and manual trans towing and I prefer the auto. Flat ground is ok but up and down hill requires a bit more skill and attention with the manual, have to be a little quicker on the shifts and focus on the right time to shift, the auto is a little easier because you can just move the shifter up or down as needed and the computer in the trans adjusts as necessary. Plus the Tow/Hual mode with the auto transmissions really help alot when pulling a load.

Having done both, I prefer the auto over manual with either a diesel or big block.

[rich weyand]

For towing, either an sbc cammed for 400+ lbft low in the rpm range, or a bbc.

Also, for towing, an automatic.  TH350 is good up into the 420-430 lbft range, after that you need to go to the TH400.

[LTZ C20]

Rich has a point with the sbc cammed for over 400 ftlbs. I built my current sbc in my truck off of some of Rich's guidance and it produces around 425 ftlbs at around 2500rpm, which is right in the middle of my power range with the beefed up 4L60 I have behind it. The engine pulls great and empty with no load it's a land rocket but next time I build anything for towing I'm going to go with a D-max. I'm not a pure diesel guy but I drive them every day so I have equal love for both gas and diesel engines.

Btw, Rich is the gooroo when it comes finding the exact cam for your purpose, he really really knows his stuff. Lots of members here, including myself trust his opinion.

[The Donchy Vetah]

Man those  small blocks are pretty potent then.   And to add onto the trans question is the clutch might take much abuse in a manual when towing, however, I am one that enjoys shifting.Thanks Fellas for all the input. Ok, my last question is if you are to hunt for a diesel in junkyard, which one would be ideal besides the gm 6.2/6.5l?

[LTZ C20]

The 5.7 converted diesels are crap, overall a crappy engine, don't think twice about it.

The 6.2 is better, not a rockstar but the one I ever delt with (in my friends 83 K5) was solid.

The 6.5 turbo diesel was good, noisy for sure, but solid, it was everything else GM loaded on it that kinda made it problematic for some. Personally I like it for a daily driver. The diesels in the Hummer H1, (military Humvee) were solid also. We had a member do a swap of one into a k10.

The Duramax platform is great, along with the straight 6 5.3L Isuzu diesel that's in the Isuzu and GM W-body work trucks. And little info tid bit for you, Isuzu and GM developed the Duramax platform.

And from what I've heard from members here any Cummins platform is also great.

Anything from the F-word company is not even worth looking at in my opinion lol I'm completely biased towards that company anyway. For me it's GM or nothing.

[roundhouse]

The 5.7 converted diesels are crap, overall a crappy engine, don't think twice about it.

The 6.2 is better, not a rockstar but the one I ever delt with (in my friends 83 K5) was solid.

The 6.5 turbo diesel was good, noisy for sure, but solid, it was everything else GM loaded on it that kinda made it problematic for some. Personally I like it for a daily driver. The diesels in the Hummer H1, (military Humvee) were solid also. We had a member do a swap of one into a k10.

The Duramax platform is great, along with the straight 6 5.3L Isuzu diesel that's in the Isuzu and GM W-body work trucks. And little info tid bit for you, Isuzu and GM developed the Duramax platform.

And from what I've heard from members here any Cummins platform is also great.

Anything from the F-word company is not even worth looking at in my opinion lol I'm completely biased towards that company anyway. For me it's GM or nothing.

GM didn't design any of their diesel engines except the garbage 5.7
Detroit designed the 6.2
International designed the 7.3 in the fords and Isuzu designed the dura max

At least dodge didn't try to hide who actually made the diesels they put in their trucks


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[Irish_Alley]

At least dodge didn't try to hide who actually made the diesels they put in their trucks

ford didnt hesitate to put a blue oval on the 5.9 cummins they used

[The Donchy Vetah]

Ok. I could not pass up on a good running 4.3 5 speed combo. (Yeah weak engine) quite cheap......... So the swap fun will begin. Soon

[87max]

Love to know where someone got complete truck with dmax & Allison for a grand. I'll take a six pack

[LTZ C20]

Love to know where someone got complete truck with dmax & Allison for a grand. I'll take a six pack

I'm probably wrong on the under a grand part but still, anything under 5 grand still seems worth it because a bare D-max long block is about 8000 bucks brand new, that's just the engine itself...

[Captkaos]

The 4.3L is going to be really weak in the department of towing in a 1Ton dually.

[LTZ C20]

The 4.3L is going to be really weak in the department of towing in a 1Ton dually.

Agree with this here unfortunately, I would venture to say your new max speed with a 4.3 is 60 mph, anything past that is gonna be real work. That's unloaded too, put a case of coors in the bed, game over. Sorry to say, you probably will come to find the 4.3....disappointing to say the least.