Posted by Brian in Oregon on Thursday, November 09, 2000 at 17:57:22:
In Reply to: Engine Swaps for 1/2 Ton posted by Tim Mooney on Thursday, November 09, 2000 at 15:49:48:
Most 1/2 ton WC engine swaps have been either Dodge 318 or Chev 350, usually with a short tailshaft auto and transfer case moved back or with a married transfer.
The problem with inline sixes is the length. It is a tight fit.
I have a 1/2 ton Command Car chassis that has been fitted with an International Harvaster I-6, probably a Silver Diamond 220 cu in. It appears to be mated to the original bellhousing, but I have not taken the time to really check it out since I'm going to drop a 318 in, when I get around to it. These older International engines are overhead valve designs, but they are dated. They do not have full mainbearing support (they have a mainbearing for every two rod bearings, not for each one). Their max RPM is limited compared to more modern engines.
A friend tried to install a Slant Six into his 41 WC. He said he gave up because the slant of the rear of the engine would require substantial hacking of the passenger side of the firewall. I have not measure this to confirm, because my cab is off my frame. But it makes sense as the rear of the flathead was in a notch in the firewall. The 41 WC probably has the tightest engine compartment of all the military Dodges. I do not know if even a Ford 240 or 300 would fit.
It is my understanding that the early Hemi's will directly bolt to the existing bellhousing. I'd like to know if the 318A engine will also bolt to it, since it is based on the early Hemi block, not the LA block (273, 318LA, etc.).
I will say that the 41 WC is more suited to a modern inline six than the 42 WC and M37, sinply because the axles are 4.89 instead of 5.83. Six bangers do not like high sustained RPM's. Speaking of axles, that brings up another point - the axles on the 41 are weaker than the M37. So you need to be careful with how much power you add. The ring gear is smaller.
Another factor is the transfer case. It is a single speed. The easiest and cleanest resolution is to replace the transfer with a married unit. However, a modern divorced two-speed transfer could be used. You'll probably have to set it back. At one time, before I decided to stick to a 318, I was going to use a Ford 351W, a short C-6 auto, and move the transfer case back. I was going to use 3/16" steel plate from frame rail to frame rail overlapping the rear of the existing crossmember and bolt the transfer to it. The rear driveline would be sectioned and the sectioned peice added to the front driveline. My frame turned out to have four major cracks in it and heavy body cancer at the main rear crossmember/frame junctions, so the whole project go set aside until I found the Command Car frame.
One problem with most of these 1/2 ton swaps has been the emergency brake. It is mounted on the back of the transmission, so unlike the M37, you have to either use a manual trans with an e-brake, or if an auto, you need to add an e-brake to the back of the transfer case.
Another issue is the radiator. I've talked to one owner who put a 318 into his 41 WC and he had no cooling problems. But one who put in a Chev 400 had constant boilovers (and yes, it was the "good" block with the steam holes). I have not found a modern radiator that will fit, and a custom radiator would be very expensive.