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Discussion Starter #1
I have a 1984 Chevy half ton with a 305 and th350 transmission. Its 4wd and I'm assuming its a np208 tcase? I'm looking to buy a 86' one ton thats got a 454 and 4 speed manual. The problem is its 2wd. SO... How would I convert the c30 to 4wd? Will the np208 bolt up? Also would I be able to just swap the front axles? And how bout the driveshafts? Would the rear ones swap out or would they not hold up behind the 454? I'm new to swaps so any advice is much needed. I also know that the np205 is the best, however I'd like to work with what I got, as well as the np208 has a better LO gear. Thanks!
 

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NCOR
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8,451 Posts
Ok, here we go.

You have to change the output shaft in the transmission and the input in the transfer case.

The SM465 4wd outputs were only 10 spline and 32 spline. If you want to use a 208 (meh) you would want the 32 spline output as there are no 10 spline 208 inputs to the best of my knowledge.

The TH350 has a 27 spline output, meaning the 208 behind it is a 27 spline input and thus directly SM465 incompatible.

My suggestion would be run a divorced 205 off the 2wd SM465 if you have the room or find a SM465/205 pair in a junkyard and run that pair. I wouldn't run all that trouble for a 208.
 

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Discussion Starter #3
Okay so say I wanted to keep the 84 as is, and just add 4wd to the 86'. What all is needed? Obviously the driveshafts, axle and t case. Is this as straight forward of a swap as I'm thinking? or is this going to be a massive pain? Im getting the 86' for $700, and its only got 60k on it. The only issue is that it needs minor brake work.
 

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NCOR
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8,451 Posts
Okay so say I wanted to keep the 84 as is, and just add 4wd to the 86'. What all is needed? Obviously the driveshafts, axle and t case. Is this as straight forward of a swap as I'm thinking? or is this going to be a massive pain? Im getting the 86' for $700, and its only got 60k on it. The only issue is that it needs minor brake work.
You'll have to put in a new trans tunnel as well as engine cross member (to clear the front axle), install leaf spring hangers and springs, front axle, drive lines (front and shorten rear or JY takeout), and t-case. Then you'll need either a 4wd steering box to retain factory push/pull or keep the 2wd box and run an aftermarket crossover setup.
 

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Discussion Starter #5
So in the end, would it be easier just to swap the 454 into the k10 and find a Nv4500 and tcase to throw in behind it? It seems much more complicated to swap to 4wd than do an auto to manual swap. No matter which route I take, I'm gonna want atleast a 350 in the k10. I don't mean to go in circles, I'm just trying to grasp how to do this. I'm still in high school (trying to do this with a part time job) so I really only have one shot at this.

And with this 454 only having 60k on it, should I still rebuild it while its out of the truck? Also just out of curiosity, I've got an edelbrock 650 on my 305, would that still mount to the 454? I love the carb but its almost too much for the little engine that could.
 
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