W500 Cummins conversion

[farmallwayne]

I am pretty much determined to put a cummins 5.9 in this w500. As we all know the axle ratio is going to be a problem that will have to be overcome.

According to my calculations 2000 rmp .75 od ratio and 6.80 axle ratio and 37" tire diameter is going to put me at a whopping 45mph....

This is assmuming I am using the nv4500 5 speed out of a dodge pickup.

What other transmissions options do I have. It has to be a manual no automatics allowed.

I need somthing with a .50 od ratio or close to it.

Thanks

[MoparNorm]

I'd recalculate, those trucks stock would "cruise" at 55 mph, the NV4500 should improve that by 25%. The stock tire size may have been a bit closer to 39", although bigger sizes will fit.
MN

[mattsoldmopars]

Yeah

My W500 has 9.00-20's on it and does not have a O.D. trans and it will run 65 mph pretty easy. I never got around to hooking up the tach to see what rpm's it is spinning but it seems to be ok. Does not sound like it is going to blow it up either. But my truck has a 413 out of a D800 Dodge LCF so it can handle more rpm then most 318's.

[JimmieD]

Yeah, unfortunately those numbers are correct, Wayne. One possible option is to install the Bosch #1-464-650-366 governor spring in the fuel injection pump which allows a redline of 3,200. There's also a 4,000 rpm spring but that's too high to get any useable power out of a 6B. These springs are for the 1srt Gen Bosch VE pump, not the 'P' pump.

Another option is to install an overdrive to the rear axle for use only when you're in 2X. I've never heard of a .50 o'd tranny, but not saying they don't exist.

[MoparNorm]

That's an option but poses some issues with the 4WD.....
MN

[JimmieD]

Yeah, I know you have far more direct experience there, so I was throwing it out for just that kind of comment on feasability.

[MoparNorm]

Oh, many of them had a two speed rear end in D models, I'm more worried about driver error than the feasibility
It could be done...with a big red waring light and 4WD lockout on the dash!

[Sickcall]

I've got a couple of eaton 2 spd rear ends with electric solenoids. From mid 50 K series trucks. They are big and heavy!

[chollo11]

Most of the T-56's used in late model GM f-bodies and corvettes has a .5 6th gear. They can be built to handle the tq of a 6bt, but I don't know how they would do with a lot of weight, or if any adapters to the cummins are available. You might try to search for a viper spec t-56, which have a much higher tq rating than the gm versions, but I don't know if they have the .5 6th.

[JimmieD]

Matt might have the best and cheapest solution with the 9.00/20's.

Welcome Chollo! What's a T-56? I'm kind of transmission challenged...

[chollo11]

Thanks Jimmie, I've been lurking around this site for a while and found a ton of good info. The t-56 is a car tranny found behind mustang cobras, ls1 gms, and dodge vipers. 1st gear is a little short for truck use , but other than that I think it would be strong enough for a truck. Heres some info on th viper spec unit, which is rated for 650 ft/lbs. http://www.ddperformance.com/GM%20T56.htm

[JimmieD]

Thanks, Chollo! interesting, looks like a pretty good tranny. A guy might be able to use the right gear sets with it and still have some acceptable truck performance. I find the whole secret is a balanced system with all parts matched to one final obective. Not that I always succeed, but the theory is good ha haha!

[Brian]

I Don't Understand...

Why tires would not be the first thing to look at here rather than an exotic transmission? Like Matt, my W500 came stock with 9.00x20 tires and don't see why 11.00x20 would not work. A gear vendor's style driveline overdrive may also be of service, though like MN said, you would want to be careful about not using it while in 4wd.

[onetonwagon]

If I remember correctly, my '64 W-500 has about 4' of driveline, yokes and u-joints between the tranny ( mines a NP 540) and transfer case. Could a guy install a Gear Venders in that space and not have to worry about using it in 4 wd?

[JimmieD]

Yes you can, and I think they mention something like that on their website, or maybe it's US Gear, one of them.