2wd to 4wd conversion questions

[Lated]

I am considering converting my '70 C10 to 4wd and have a few questions. Basically, the idea that has been wheelin' around in my head is to build a lowered (not sure how much) full-time 4wd truck. I plan on putting a np203 behind a 700r4.

1. Does a full time 4wd np203 require special hubs or just the same automatic hubs that could be used with a part time transfer case?

2a. What type of front axle should I be looking for? I would prefer IFS but a straight axle would be alright.

2b. If IFS is a possibility, what year truck should I look for to pull the front out of?

3. I've never seen a chevy IFS setup so I'm not really sure how it works. Is the diff. solidly mounted (no vertical movement) with the axle shafts pivoting on either side or does the diff. have some vertical movement to it as well? (Not sure that was worded well, but hopefully it gets the idea across)

Obviously there would be quite a lot of fabrication involved in this project. I'd probably end up needing to move the engine back to allow for vertical movement of the axle if going with a straight axle. Still in the extreme early stages of planning so please don't beat me up too much for stupid questions. I'm sure there will be more questions to come.

[martindc1]

If you want to do a full time 4wd truck, just look around for a 73 up full time 4wd pickup to use as a donor truck. They can be found pretty cheap and you would end up saving money, otherwise you would get nickel and dimed to death with the small things. Plus you could sell off the used parts to make back some cash. I saw one for sale not too long ago locally for $1200, it wasn't in bad shape really. They don't it too high in stock form really.

[Lated]

If I end up deciding to go with the np203 I will probably look for a later 70s donor. I think the easiest way to get the truck as low as I want and AWD is to use the front and rear axles from a late model BMW. Only problem is the front output from the np203 is on the passenger side and the BMW is on the driver side. Solution - np242 out of a HMMWV. It would require an adapter to mate up to the 700 but so would the np203. The main appeal of the BMW axle is its intended ride height, it would be perfect without the need for lowering and the driveshaft runs right next to the oil pan on the BMW's I6 so hopefully it would work in the truck (I don't know if it would work with my planned 400 though). I don't know which direction the BMW axle is designed to spin vs a GM axle (or if it matters). I guess my next step is to find a BMW to check out.

[OrrieG]

Not an expert but I think other models of 203's (Ford? Dodge?) had driver side drops.

[Lated]

Originally Posted by OrrieG

Not an expert but I think other models of 203's (Ford? Dodge?) had driver side drops.

Thanks, I'll keep that in mind.

[Jason M]

You could use a Ford 203 with a Chevy 27 spline input shaft from a T-350 version 203 to match the output of the 700r. A 4-wheel drive 700r would be the best doner and get it with the factory 241 adapter, not the 231 adapter.

This way all you need to is re-drill the 6 bolt pattern onto the face of the 203 and theres plenty of extra meet to do it.

Jason.

[Lated]

Originally Posted by Jason M

You could use a Ford 203 with a Chevy 27 spline input shaft from a T-350 version 203 to match the output of the 700r. A 4-wheel drive 700r would be the best doner and get it with the factory 241 adapter, not the 231 adapter.

This way all you need to is re-drill the 6 bolt pattern onto the face of the 203 and theres plenty of extra meet to do it.

Jason.

Would I need to shorten the output shaft of the 700r4? I read somewhere it needed to be shortened for a GM 203, would it be the same for the Ford?

Anyone know how much torque a stock 203 will handle, or how to strengthen one?

[LONGHAIR]

Ford 203s are a lot harder to find than Chevys, there were a lot less of them from the start. The IFS is going to be the hard part. Trying to mate it to the older frame would be difficult, if not impossible. Grafting the front section of the later-model frame to the older one seems a lot more plausable. Maybe swapping the older cab to the entire newer frame would be even better?

[Lated]

Originally Posted by OrrieG

Not an expert but I think other models of 203's (Ford? Dodge?) had driver side drops.

Talked to a friend at work with a 203 in a '79 Dodge. He said he thinks the front drop was on the passenger side but doesn't remember for sure since he left the truck at his dad's house and hasn't seen the truck in awhile. Looks like the options are a Ford 203 or a 242. I think it's time to visit a junkyard so I can look at options and try to get some measurements.