Hell mine doesn't even fit in my garage and its barely lifted...
the lowest gearing you can get for 1500 axles is 4.88 but I'm assuming since your going with larger than 35" tires you are going with heavier axles? you may find since your building from frame up it may be cheaper and easier to go with a heavier 2500 for other upgrades like wide leaf perches and heavier power steering setup...(plus heavier axles)

 

Dude, if you knew the plans, you'd turn green with envy......
I'm going with a specialized axle that comes in a 4.91 ratio.
I talked with a guy from Hughes Engines and he said to go with the 360, and to stroke it to 408. And does anyone know about the six speed?

 

The 6-speed is an NV5600 and only came mounted to the diesels and V10s in the 2500 and 3500 trucks. The input shaft on the 5600 is larger than the output on the 360 so some adaptation would need to be done there. Not sure if the bolt pattern on the bell housing will fit the 360. I'm guessing it probably will.

I'd go with the NV4500. It's a 5-speed but has more than enough strength to handle just about anything the 360 (or 408) can put through it, assuming you have a good clutch. Shoot, the NV4500 handles built cummins motors!

 

Thats not a good idea at all. If it blows up and you need your truck fixed fast there will be no overnight a ration like that. You would be better off getting 4.88.

But hey what do I know.

 

Well, not to argue; but I'm not afraid of breaking the NV4500, I'm wondering if the extra gear would be needed to pull 37's. From what I understand, the NV5600 splits third gear into two gears. But if 37's are tame enough to be handled without losing performance, I'd rather stick with a five speed. Thoughts, anyone?

 

Why would I be envious? The truck you are building sounds completely useless in the desert. More like bro-fab then anything.

 

and what's wrong with a backyard build???

riddle me that...

 

Sounds like a cool build to me, how about a 4bt cummins swap?

 

screw the 4bt, put a 12 valve in it

 

Who said anything about backyard building..? That's where half of my Ranger, and all of the stuff I have built for my ram was built.