The Stovebolt Site Forums The Shop Area Driveline Need help for converting to NAPCO 4x4 - 1954 Chevy

I find myself with a 54 Chevy that I want to convert to 4x4 (no frame swap) and with no good source of specific information. I'm hoping one of you might have some information or pictures of the front axle and suspension on a pre55 Napco truck you could share. Specifically did they do anything different with the front leafs or are they mounted in the original locations.

Sandman, I can put a "shot out" to our "Napco Man" - he may be able to help. HERE IS one of his trucks.

Also, there are a number of Bolters with "NAPCO" in their screen name. See if any of these names jump out at you.

There are a couple episodes of My Classic Cars that feature Chevy NAPCO conversions.

58 Appache


59 Apache NAPCO installed at factory, not aftermarket.

The AD truck NAPCO conversions are a lot trickier than 55.2-59 for a couple reasons. It was only offered on heavier trucks, because of the closed driveline on the half tons. The other issue is how the frame tapers in at the front, making the leaf springs angled. They do not match the perches on the NAPCO front axle and the perches are cast into the axle and cannot be moved. I had hoped to convert a ‘51 3100 I had years ago and never could figure out how to do it best. I had the complete conversion set sitting around and never got it done. I sold the truck, but still keep all the NAPCO parts, in case I find that perfect truck. Good luck with the project. I hope someone jumps on here with an answer for you.
Take care, George

Dude has a 4400.
No worries though George. I typed out a diatribe with more details than you did and deleted it once I noticed that he has a big truck

Wonder how much could be found using our Search here? Using the Advance Feature. Following Dean's instructions, and using the advance feature, really can spit out a lot of helpful info. Especially since you can delete (-) stuff you don't want (such as size specs) as you set up the search.

George should still be able to help, he has a 1954 2-ton NAPCO...

Mike B

"You really can make a silk purse from a sow's ear, but it makes the pig look funny, and it doesn't hear very well afterwards!" Trying to reinvent the wheel instead of letting people with the manufacturing capability and the engineering staff to do it right shoulder the load seems like a waste of time, effort, and money. I'd find a suitable size and load capacity modern 4X4 chassis, and do a sheet metal swap. You'll end up with a 50 year newer chassis that actually works, with old-looking sheet metal on it.
Jerry

If you find a '54 Napco front axle, it will likely require a complete rebuild and parts for any Napco axle are hard to find, let alone a '54 axle.
You will need to find a Napco crossmember for the transfer case which fits a '54 frame.
You will need to find a Napco transfer case and be ready to rebuild it. Again, parts are hard to find.

Napco trucks are cool, but they are not anything like a modern 4X4 in performance and reliability.

Now knowing that it’s a 4400 opens up another can of worms. The NAPCO parts for the big trucks are extremely hard to find. You could probably find a military front axle from a WWII era truck with spring perches that would work and possibly a transfer case out of the same truck, but it would be tough to do. I agree that a modern day frame/running gear is the easiest solution.

I appreciate all the responses. This post has been butchered and moved by mods so the original intent has been lost. I do have a 54 4400. I am looking for pictures/understanding on how NAPCO dealt with the tapered front frame to hang what from my searching and best guess they did not necessarily hang the springs tapered. I do not have NAPCO parts but am scrounging around junkyards for parts that fit my idea. I am not interested in a chassis swap.

You sir seem to have a wealth of knowledge and one of the ones my original post(which was moved) in the NAPCO owners thread was trying to ask my question to.

Could you explain this further and potentially post some pictures of your kit? Are the NAPCO front springs mounted Parallel to each other? Did they use/make new Mount Points for on the frame? If this is the case I am more than capable to make/scrounge some new hangers.

For the rear axle I read that NAPCO essentially extended the rear hangers 8in to match the height gained by the straight axle in the front.

"My mind is made up- - - - -don't confuse me with facts!" I believe we've seen this movie before! NAPCO was an interesting approach to meeting a specific need for offroad vehicles, before the major manufacturers saw the advantage in offereng limited production specialty vehicles. The Conestoga wagons that traveled west in the mid 1800s were another example of specialized vehicles built for a specific purpose. Replicating either one with all-original parts and pieces would be equally difficult, and expensive. Have fun with your project!
Jerry

On the front springs, the 47-55.1 FAM shows everything up to 4100 trucks (as high as it goes) with essentially the same spring mounting dimensions (the only thing that gets changed is the width and number of spring leaves.)

I have doubts that NAPCO would have messed with the spring upper mounts, and don't see how it would make any difference whether the springs were mounted at an angle or parallel to each other. The little bit of angle at the spring pad at the axle isn't really going to make a difference in how the springs perform. I think if you do find someone with a 4400 NAPCO truck that can provide photos, that the upper spring mounts will be in the stock position. But like NAPCO Man said, if the distance between spring pads won't match up, you're pretty much done. Maybe someone with a 55.2 and up FAM can find the spring pad dimensions so you can see how far off they might be, and if there's a way to adapt the axle to fit.
Like the other guys said, your biggest problem is going to be finding the parts. I also wish you success in your project.

I believe you will find out that your best option is to use a more modern set of axles. I have done that to a TF truck using the original frame. Finding and installing a napco will be difficult.
I would myself never attempt to add such a monster bit of kit to a 2WD 4400. But anyway here is a 4400.
Click

It's a 55.2/56

better off buying a "napco" 4400. Not that popular and probably there are good ones for cheap. Save you huge headaches and backaches and buying big rig tools. jacks, air tools, etc. And you would have two trucks to make one nice and sell left over parts to recoup. I've done that many times to get what I need. I can't wait years for someone to part out what I need, near me.
Whatever you do, the fabbing will be YOUGE.

I've taken this "big rig" apart with my tools I've bought for working on my dinky Toyota and Land Rover, I'm not seeing anything special about the 4400 vs a 1/2ton truck. This is the kind of picture and information I'm looking for, this early 80s Chevy has out boarded parallel front springs and a tapered frame. I would appreciate any pictures anyone could provide of their NAPCO kit.

I have the answer from a Facebook group. For anyone else interested. On the ad trucks Napco did not relocate the springs but welded their spring perches at an angle on the axle.

Interesting. Thanks for reporting back.

Shoot the moon and put a Wilcox swivel in the frame!

Jerry

Sorry, I haven’t checked in for awhile. It sounds like things are figured out, but I figured I would try to post pictures of my 2 Ton NAPCO front axle. If I can’t get the pics posted, I’ll email them to Peggy to post. I have a spare transfer case, but I don’t have any interest in selling it right now. I can try to find a model number if it helps your quest. Hopefully the pictures show the taper in the frame and the fixed spring perches. As for the rear, block spacers and longer u-bolts are all that’s required . Let me know if I can get any other info for you.

Also, you don’t have to find a crossmember for the t-case as you will be replacing the carrier bearing support with the t-case. If you have the correct parts, the installation is very straightforward. I have the installation manual somewhere and it tells you which existing holes to use and whether or not you need to drill them out larger. The swap can easily be done in a day. Finding the parts is the rub.

Exactly the pictures I was looking for, Thank you!
My quest is a far cry from even finding NAPCO parts and is involving a lot of custom work. I was hoping to find that NAPCO made some hangers that I could copy but I will be making my own. In the end my front springs will be parallel to each other and have the shackle reveresed towards the rear. Queue up Johnny Cash One Piece at a Time as I scrounge around for parts that were never meant to go together.

I’m glad they helped out. Let me know if you need anything else.