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I tried doin a search on this topic because i was interested in doing it down the road. what do i need to do to swap my 3100 49 to a 4x4 napco truck. I remember reading somewhere that if i found a 50s napco it would be a straight bolt up (are the cab/bed mounts the same?). is this true if so what years would bolt right up. any input on the swap would be awsome thanks

I don't know for sure, but my guess is that 49-53 cabs all bolt on the same, and would be interchangeable.

My guess would be that being is the truck has a leaf spring front end all you would need to do is find a front axle of the correct width with the spring perches in the correct place and the wheel bolt pattern and gear ratio that matches the rear and bolt it in. I would most likely start by buying a whole 80s 4X4 parts truck with good running gear a cheap rust bucket would serfice. Then I would alter the axles for width and mounting. Your stock steering should be easy to make work also and if the truck you chose is a 4 speed you could most likely have a machinist bore the pilot hole in your bell housing to except the later model SM465 as the only mounting difference between the stock 420 in your truck and the SM465 is the pilot bearing support and if you need any cross members for the transmission and transfer case you can always modify the ones from the parts truck. Keep the parts truck till the end of the project and when finished put any usable parts left on ebay or Craig’s List and scrap the rest. In less of course you are looking to have a more authentic NAPCO.

Pre '55 NAPCO trucks are pretty rare. Fames on '55 2nd and later trucks are quite a bit different than those of earlier trucks.

One way or the other I don't see where it could be too tuff to change any 2WD truck that has leaf springs at both ends to a 4WD

Yah i was just kicking the idea around and thought that i might of heard the later 50s napco truck frames could be swapped on, and i thought if its that easy i might as well, but i think for now ill keep it the way it is thanks for the input

Here's the big stumbling block, there were no 1/2 ton Napcos pre-'55, only 3/4 and 1 ton. Napco didn't produce any 1/2 ton conversions until they went to the open driveling in '55. HevyHauler has probably the best solution if you want to convert your 1/2 ton. You will have to change the transmission to one that will accept the later t-case, there may be some machining of the bellhousing required as well to make the later trans (larger bore id) to fit.

'49chev,

I'm currently converting my '59 3800 to a 4x4. I bought a Dana 60 front axle from a wrecker (sorry, automotive recycler) that has the exact spring spacing as my '59, had some u-bolts made up and it bolted right up. I'm converting over to power steering, so that's no big deal.

Find a 'divorce mount' NP-205 transfer case from an early '70's International pickup, that way you won't have to do anything to your original driveline, just a short driveshaft from the tranny to the transfer case, one to the front axle and a shorter one to the rear axle.

Check out the progress here: http://community.webshots.com/user/Lane9999

Lane

Lane, good advice, but on the AD 1/2 tons, they use a torque tube driveline, so the trans will have to be swapped to work with really any T-case, divorced or integral. There is another option on a divorced style T-case, an NP 203 from a '70s military Dodge. Boyce equipment has them. doing it with the divorced style T-case will alow for use af an SM 420 trans from a '47-'66 open driveline truck, which will bolt up to the existing bellhousing with no mods.

LB there are many married transfer cases that will bolt up to the SM420 in fact the SM420 is one of the most popular 4X4 gear boxes made because it is so short and has the lowest first gear

Actually, I did know about the conversion parts to do that, I didn't think of that when I posted. Advance Adapters makes the parts.