Chev-odge: ‘71 K20 Cummins build

[fishnixon]

Now the proverbial wrench shot of the removal of the rear driveshaft…which starts the frame preparation. Got it out and next, the front shaft.

[fishnixon]

And here’s a couple pics of the frame of my ‘71 Chevy K20.

[Dieselwrencher]

Nice project. Unfortunately you won't be able to put the Cummins balancer in the same place as the small block chevy without cutting the firewall severely. I've seen the dodge cross member used in these before. You can make it fit. I usually just made my own. Do you have any plans to replace the leaf springs or lift the truck any? We have a diesel conversion section in the engine area of this forum with a lot of builds in it as well.

[fishnixon]

Originally Posted by Dieselwrencher

Nice project. Unfortunately you won't be able to put the Cummins balancer in the same place as the small block chevy without cutting the firewall severely. I've seen the dodge cross member used in these before. You can make it fit. I usually just made my own. Do you have any plans to replace the leaf springs or lift the truck any? We have a diesel conversion section in the engine area of this forum with a lot of builds in it as well.

Thanks! Good feedback…My goal is to be able to compare the small block fore and aft and then find the location for the Cummins, so I do not have to cut the firewall. I’ll be using electric fans to make room in the front.

I’ll check out the diesel section. Perhaps I’ll find a “common” Mopar crossmember to Chevy frame location on the frame I can use. Would you know of such a location that I can map out on the frame?

I do plan on replacing all leaf springs and am hoping for a 4 inch lift while using the Dodge front and rear differentials (reportedly with 3.08 gears). I need to gain knowledge of a spring pack that will hold up the heavy weight of the Cummins while getting the 4 inch lift. Do you know of a leaf pack package that I could purchase to accomplish this?

Any help is accepted and appreciated. The easier (through other’s experience) the better! Thanks!

[sfont66]

Cool project!
I would love to have a Cummins swapped K20.
I see a few other trucks in the background, looks like you have a truck for any job, from 1/2 ton hot rod to heavy hauler.
Keep up the good work!

[fishnixon]

Originally Posted by sfont66

Cool project!
I would love to have a Cummins swapped K20.
I see a few other trucks in the background, looks like you have a truck for any job, from 1/2 ton hot rod to heavy hauler.
Keep up the good work!

Yea, the Cummins dream is about to get real. Love these trucks…it’s a sickness, I tell you…when you grow up playing with a few handfuls of HotWheels, what do people expect? Heh heh…thanks for the encouragement. Tomorrow, I hope to yank out the power train. Stay tuned!

[72 tigger]

Originally Posted by fishnixon

Thank you, I’ve always wanted one…how difficult was it to put the Chevy on the Dodge chassis?

Rob, sorry I missed your question. I had to cut the frame to achieve the 127” WB and then make body mounts. It took about 4 months to build.
You’re making good progress!

[fishnixon]

Originally Posted by 72 tigger

Rob, sorry I missed your question. I had to cut the frame to achieve the 127” WB and then make body mounts. It took about 4 months to build.
You’re making good progress!

Nice! 4 months is not too bad at all…I hope to get things rolling nicely by then. Thank you!

[fishnixon]

Lining up the frame, I start by disconnecting the front driveshaft, then the motor mounts.

[fishnixon]

Getting after the transfer case

[fishnixon]

Transmission mount bolts…

[fishnixon]

Engine, trans and transfer case coming out…

[fishnixon]

Progress!

[fishnixon]

Put the frame outside for now because I had to do a brake job on a daily driver, and got the engine on a stand for storage.

[Dieselwrencher]

Originally Posted by fishnixon

Thanks! Good feedback…My goal is to be able to compare the small block fore and aft and then find the location for the Cummins, so I do not have to cut the firewall. I’ll be using electric fans to make room in the front.

I’ll check out the diesel section. Perhaps I’ll find a “common” Mopar crossmember to Chevy frame location on the frame I can use. Would you know of such a location that I can map out on the frame?

I do plan on replacing all leaf springs and am hoping for a 4 inch lift while using the Dodge front and rear differentials (reportedly with 3.08 gears). I need to gain knowledge of a spring pack that will hold up the heavy weight of the Cummins while getting the 4 inch lift. Do you know of a leaf pack package that I could purchase to accomplish this?

Any help is accepted and appreciated. The easier (through other’s experience) the better! Thanks!

I have rough country 4" lift springs for a square body on my truck. I converted my truck to 4x4 and used the stock front hangers. I had to cut the frame for the shackle hanger so that allowed me to use the square body longer spring. I'm sure the 4" 67-72 springs will hold the weight as well. They will just ride more rough due to the shorter length.

If you have 3.08 gears you have the D61 and D71 axles. There used to be no aftermarket gears for those axles. There are some now.

It looks like you have a good collection of trucks there. Are you using the old powertrain in another project?

[fishnixon]

Originally Posted by Dieselwrencher

I have rough country 4" lift springs for a square body on my truck. I converted my truck to 4x4 and used the stock front hangers. I had to cut the frame for the shackle hanger so that allowed me to use the square body longer spring. I'm sure the 4" 67-72 springs will hold the weight as well. They will just ride more rough due to the shorter length.

If you have 3.08 gears you have the D61 and D71 axles. There used to be no aftermarket gears for those axles. There are some now.

It looks like you have a good collection of trucks there. Are you using the old powertrain in another project?

Good info…thanks. Yes, I have a few trucks. The 350/350 combo will be added to the stock pile, awaiting something or someone. I always thought that the small blocks I have would be great in a nova or something. The yellow C10 in back has the 402 in it and some nice options included. I have to get this Cummins together, then another C10 that’s on the rack with the drivetrain already done. I’d like to get a muscle car but I’d better sell one or two of these guys first. Running out of room and time. Heh heh…