How much trouble would be involved to put a 01 Ram 1500 rear axle and front suspension to a 1974 Dodge D150?

 

A lot.

 

The rear axle might actually bolt in. But its quite a bit wider.

 

pretty sure you need to move the spring mounts to make it work but even then it is not really worth it. it would be easier to swap a older body onto a the newer frame than it would be to swap the newer parts onto an old frame.

 

I have Dodge trucks from '75 to '96... and the rear spring spacing is the same across the board. '74 and '01 should be the same body style range.

When I put a '95 diff in my '93, I added spacers to the front to even out the track widths... and also used the newer wheels.

This guy but the later coil sprung diff in an older crewcab.
https://www.dieseltruckresource.com/...-build-285945/

 

Say what? The body style changed dramatically in 94....... I don't anything anything is the same between them.

 

Big changes for sure... but they left the rear spring spacing the same, and so is the rear frame rail spacing.

 

Better yet get a(second gen) frame motor and everything and swap the 74 body on it!

 

With a Cummins.

 

but when it comes to crew cabs they are a bit different. some people go all out when they convert them to 4x4 since you rarely find one that is not 2wd and it is not like you find crew cab 4x4 frames sitting around. when you build custom you can use whatever parts you want under it