has anyone put a 25 inch flathead in a 39-47 truck?

[1940 PT-105]

I just bought a 1940 Plymouth truck. Mostly complete, but missing fan, water pump, air cleaner and oil filter. I was planning on simply replacing those items and driving it, but my block (the 23 inch version) is cracked.

There is a running Chrysler industrial block for sale locally, but I'm guessing it's the 25 inch version.

Has anyone done this swap on this bodystyle trucK? Or does anyone in the Denver, CO area have a 23 inch block for sale?

From what I have read on this site, It sounds like I would have to fabricate a new front crossmember and potentially relocate the radiator. I don't have any issues building a crossmember, but I don't know if I care to chance not being able to fit my radiator.

Thanks,

Dave

[Young Ed]

Dave you're in luck. The bigger trucks had a 25" engine. So if you find a radiator from one of those you can use that or you should be able to move yours to the other side of the U. I've also heard of reversing the U. Then you can either weld extensions on the front mount to extend it back to the factory bolts in the crossmember or the one that I had someone welded angle iron on the front crossmember to bolt the mount to. This did lift the engine up about an inch in the front.

[Reg Evans]

I've done it 4 different times. A 47,a 48,and 2 52's. All 1/2 tons. Pretty much like Ed said.

Here's my 47 after climbing 3000' to a camp site about 15 years ago.

[1940 PT-105]

Thanks for the replies.

I put the grill and "U" back on the frame to get some idea of what it will take and the changes you are describing. From setting it up, it appears that the fender braces and radiator mounts are on the center line of the U channel, and will not need modification. (green line and circles) The new orientation of the U (red) will require simple tabs (yellow) in order to keep the grille in its proper location.

Were either the the middle brace (purple arrow) or the air deflector (blue arrow) removed or modified?

Looking at the new way of mounting the radiator, It doesnt' appear you can install and remove it due to lack of access to the bolts.

I like the idea of simply mounting the rad behind the U as it is, but it doesn't appear like that could work for the same reasons.

What am I missing?

[Young Ed]

The normal position of the radiator puts it competely on the firewall side of the U. I believe if you find a radiator out of a 1.5 ton it will still bolt in the same place but the sides will put the core back inside the U. You could probably have your existing radiator modified by a shop too.