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Choosing The Right Dana 60 and 14 Bolt GM For Your Swap

cosmic339

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Hey guys i wanted to Start a Thread on Choosing the right Dana 60 and 14 Bolt Gm for someone who was intrested in swapping there axles to something more modern. Any input for this thread would be great i have serached many places for info all little bits of info so he it goes.

If someone has large width dana 60 how much would they have to narrow them so that it fits perfectly under the M37?

How much would you have to narrow the 14 bolt? if at all


From what years and truck would this set of axles have to be from?

you would have to use 2 inch wide spring perches to use the stock leafs from the m37.
Isnt the normal Track width for the M37 "74" with wheels?
The Stock sizes i found for dana 60 is 69.5
The Stock sizes i found for 14 bolt GM is 67

That being said if someone wanted to go with this they can move the front spring perches about 2 inches to the outside of the frame and just a little bit for the rear on the axle. But how about narrowing?:doghead:
 

cosmic339

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I see that you still haven't simply bought a CUCV, or mounted the M37 cab/bed on a CUCV frame? :)

Where are you measuring to get track width? From drum mounting face to drum mounting face?

Ahem.... g741.org • View topic - For Sale: 4BT swapped 1954 M37, $10K -Upper Michigan - wheels are too narrow for the tires, but you get the idea.

'Tanner'
No i guess i took your words into consideration :) and i dont really like cucv they look ugly imo lol. but i was getting those measurements from a vendor that carried some of them. But i still dont understand what you mean by the wheels are too narrow for the tires? is this because he tried to make up for the big gap of 62 to 67?
 

pryorfire48

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from the offroad rock crawling world we would try to run a 12 inch wide tire on a 10 inch wide rim. I have run 12 inch wide tires on 8 inch rims with no problem. it makes the sidewalls bulge out but even air down i never busted a bead off the rim. The truck in the picture looks fine to me.
 

Lebowski

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Manitoba Canada
Some additional info:

Gm Dana 60 front spring perches center to center 32.5" (or 32" according to Pirate4x4 bible linked below)
Gm front springs outside to outside 3x"
Gm spring width 3"
Gm spring length approx 47"
Pirate Dana60 bible: http://www.pirate4x4.com/tech/billavista/60_front/
*As a note, you can run the 2.5" wide 3/4ton springs on the D60. Most aftermarket lift kit springs are 2.5" wide. I just measured my friends truck and it has 2.5" wide Tuff Country springs with 6" of lift.

M37 front axle spring perches center to center 29.25"
M37 front springs outside to outside 31.25"
M37 front spring width 2"
M37 spring length approx 45"

With those numbers, you could shorten the Gm D60 xxx" if using the original GM Dana 60 center placement spring hole (that is cast into the diff housing).

Or, you can shorten the Gm D60 xxx" if you drill a new spring centering location hole xx" inboard towards the diff (so you can move the narrower M37 spring x" inward towards the diff - remember the GM springs were 3" wide vs M37 2" wide).

Here is the passenger side spring centering hole I speak of, that is cast into the diff housing:
http://www.pirate4x4.com/tech/billavista/60_front/Boyce%20chevy%2060f%202.jpg
 
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steve6x6x6

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Some additional info:

Gm Dana 60 front spring perches center to center 31.5"
Gm front springs outside to outside 34"
Gm spring width 2.5"
Gm spring length approx 47"

M37 front axle spring perches center to center 29.25"
M37 front springs outside to outside 31.25"
M37 front spring width 2"
M37 spring length approx 45"

With those numbers, you could shorten the Gm D60 2.25" if using the original GM Dana 60 center placement spring hole (that is cast into the diff housing).

Or, you can shorten the Gm D60 2.75" if you drill a new spring centering location hole 1/4" inboard towards the diff (so you can move the narrower M37 spring 1/4" inward towards the diff - remember the GM springs were 2.5" wide vs M37 2" wide).

Here is the passenger side spring centering hole I speak of, that is cast into the diff housing:
http://www.pirate4x4.com/tech/billavista/60_front/Boyce%20chevy%2060f%202.jpg
All the info. you posted on chevy dana 60 fronts is wrong. Spring pad centers are 32 1/2", the springs are 3" wide, the 3/4 ton 4x4 are 2.5".
 

Lebowski

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Manitoba Canada
Steve,
Haha...your right. Thanks for catching that. Not sure how I put that info down, as I have three M1028's sitting in my backyard. I've gone back and made the corrections to my errored post. aua
 

nattieleather

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Cleveland, OH
The font axle has to lay 18.5 inches from hub to frame to be centered on the truck. In order to do this the right front leaf spring has to move out 1.75 inches from it's stock location. It is easier and less expensive to move the spring than it is to shorten the axle. To shorten the axle you have to not only have the axle shaft shorten and recut by a quilified shop which I think there is like just like a handful accross the US. But you also have to then correctly shorten the axle tube. Can it be done? Yes but if your not a professional machinist I wouldn't do it.

Now if Dodge had kept the frame like on the WWII vehicles meaning a straight H type frame instead of the A type the M37 is (Looking at the frame that is how I see them as Hs and As) then an axle swap would be easy peazy, but sigh it's not that way!
 

Tanner

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No i guess i took your words into consideration :) and i dont really like cucv they look ugly imo lol. but i was getting those measurements from a vendor that carried some of them. But i still dont understand what you mean by the wheels are too narrow for the tires? is this because he tried to make up for the big gap of 62 to 67?
Cos:

The rims in picture of M37 are too narrow for the engineered design of the tires being used. Sure, you can make the tire squeeze onto the rim & have the sidewalls pulled in, but you end up crowning the tire & wearing out the center of the tread when aired up to proper use for highway speeds. Tires engineers spec a certain rim width range for a reason. And people will mount tires on rims too wide or too narrow for the tire selected, but that doesn't make it right or a safe way to run the tires.

Track width is the dimension measured from the centerline of the tire tread on one tire to the centerline of the tire tread on the opposite tire on the same axle. This track width dimension can change depending on the rim offset used & width of axle. You could have a standard 65.5" width axle (measured from wheel mounting face of rotor on left to wheel mounting face of rotor on right), but mount rim/tire combos that have dished rim offsets that push the tire centerlines outward & end up with with a track width of 72"... depending on wheel width & offset, fender/frame clearances, etc... Does this make sense to you? You'll need to take into consideration the rim width & offset of the wheels you choose to use. It would be best to have your wheels on hand when you start looking into axle choices.

'Tanner'
 

Lebowski

Member
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Location
Manitoba Canada
I think a new, custom length 4340 axle shaft goes for about $300. Taking the front housing in to get one tube shortened might be about $200. If you ask around your local hot rod club you might find out where a good reputable place may be. I can see how some MV fans may want keep the track width close to original as possible.

Here is a good thread on an M37 build with full width D60 frt. Page 5 has some good pics of spring mounts in order to install a regular width D60.
g741.org • View topic - Project: Old Guard - lots of pictures
 
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nattieleather

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-

Is this second truck article by chance nattieleather's project truck that is running '79 Dodge W200 axles?

'Tanner'
Why yes it is. If you go farther not only do you see how I did the axles but also the extream body work on the cab. I haven't worked on it since August due to other commitments. Maybe this weekend.... sigh.
 

Tanner

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Why yes it is. If you go farther not only do you see how I did the axles but also the extream body work on the cab. I haven't worked on it since August due to other commitments. Maybe this weekend.... sigh.
So - you performed the swap without resorting to narrowing the axles/housings?
 

nattieleather

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Yes. I just bumbed the front spring on the passinger side out about 2 inches and now that the cab is back on and the front fenders are on for fabrication purposes I can see that the new axles don't stick out all that mutch. I'm very pleased with how the axles came out. Maybe someday I'll get to drive it... :lol:
 
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