Allison 6sp: Putting a Cat C7 engine in a Chevy C20

NobleC20

New member
Apr 16, 2014
2
0
0
I Plan on putting a Cat C7 engine in a military chevy c20
My questions are what kind of modifications will i have to the frame or to the suspension? if i use an Allison 3000transmission what kind of transfer case can i use? And will the Dana 40's thats come on the truck be able to handle the power?
 

TROJAN366

Gold Rush
Jan 13, 2012
2,474
1
38
MASS
We have a few trucks around the shop with C7s. There is a lot of wiring, they are fairly large, and they don't make a ton of power. A cummins swap seems like it would be a cheaper and easier swap. It would also have more potential to make power.
 

catman3126

Ehhh?.... You don't say?
Jul 24, 2012
2,636
0
36
NE Oregon
Dana 40's? And I started down this road once upon a time and decided against it. that engine is pretty tall and quite a bit longer then a 5.9 cummins IIRC it was 7 inches longer. and I want to say weighs several hundred more lbs then a cunmmins. I doubt the dana 40 or 44 would be up tot he weight abuse over time. ball joints wheel brearings that kinda thing. wiring really shouldnt be that bad as the ecm is on the motor itself usually. so it shoudl be doing inputs like throttle and powers and ground and keyed power. 7.2 liter also so you know ist got to be a fair amount heavier. Now if you can get a cat deal to install the marine flash file they are around 450 horse flywheel and well over a 1000 ft lbs, 300 hp rating in a truck was 870-900 ft lbs. there is some places that make injectors and I believe PDI does tuning for them. or if you can figure it out you can buy your own Cat ET tool and pay for the passwords to tune it your self but it woudl be nothing like writing EFI Live tunes. there just two numbers to mess with. Awesome yes! I knwo my truckl weighed 26K as a service truck and there was not many hills it wouldnt walk up at 70mph with ease. so if you had a few more ponies like 400-450 it would actually be a towing animal! just my thoughts on this.
 

Frankin_truck

Member
Nov 22, 2013
147
0
16
Also the allison 3000 is a huge transmission. If you could find a sae allison 1000 like from a cummins that would be easier to work with and you can always build them. :thumb:
 

mackthehack

DUH...
Apr 16, 2007
831
0
16
Like mentioned above. Dana 40's??? If its a true "military" cucv m1008 it will have a dana 60 in the front and a 14 bolt in the rear.

If those engines or trannys weigh that much like mentioned above. You've got a lot of work ahead of you to reinforce the frame. Why not look into a heavier duty truck? Like an older 2 ton or something similar? Something that has rockwell axles.

And this is your first post?...
 

Dmax87

Member
Dec 3, 2013
171
0
16
Terrible choice for an engine. I work for cat and I say that cause you will find yourself putting heui pumps and injectors left and right. You'll have say #2 injector go bad and garanteed ill put money on it you'll be replacing the remaining ones in a matter of a couple months. Not to mention how many engines I've had to pull and have sleeved due to broken rings. Shows up every time just had ford or gm replace an injector and it still has an engine miss, broken rings every time. You would have better luck with a 3126 or just a good ole 12v cummins. Sorry if I rained on your parade but I'd hate to see yah go through all that work just find you're dumping money into it. :thumb:
 

cat_dr.

Member
Feb 20, 2013
257
0
16
Jackson,Al
I also work for cat. And like already mentioned that would be the last engine I tried to use for a swap. Huei= headache


Roll Tide!
 

PureHybrid

Isuzu Shakes IT
Feb 15, 2012
3,517
501
113
Central OH
If you are dead set on a huge boat anchor out front, buy a mechanical 8.3 Cummins. It'll have a p7100 and wet liners, none of that throw away Cat bs.

It would be less time consuming to get an Allison 1000, IMO finding the right bell housing and flywheel housing on the engine would be much easier with the Cummins setup.
 

NobleC20

New member
Apr 16, 2014
2
0
0
Thanks for the replays, I think I'm going to go with a dt466 with an Allison 3060 with a power take off i have from an old firetruck, but what type of differentials and transfer case would be best for this build, i want it as a heavy hauler and to go off road.
:thumb:
 

messejme

Jazzy, Me and Max
Mar 7, 2008
741
0
16
Branchburg NJ
The 3126 and 3176 have those front timing plates that crack and spew oil but they are tough motors that can run for a long time.