numby, that's very interesting because I think my frame is a 74. I had some fenders from a 78 that I was going to use a few years ago and the bolt holes in the frame for the fenders were different. So after talking to the PO he thought it had been replaced due to a wreck many years ago. Guess, that's probably something I should have mentioned, but I had completely forgot about it.
Okay, here’s how to tell if you need to do the alterations I mentioned....
IIRC the pre-8/76 front crossmember is made up of two pieces of U channel. The top, front, and bottom are one piece and the back - the side facing toward the engine compartment - is a separate shallow U. The back piece fits inside the front and the two are hot nailed/riveted together along the rear edges both top and bottom. Kinda like this but on its side:
ll_____ll
l______l
l______l
Also riveted to the back piece are the two radiator support brackets. There is a single hole in each of those for the core support frame to bolt to.
The 77~ crossmembers are also made of two U-shaped channels BUT, at least at the top rear edge, Toyota drastically trimmed back the overlapping portions which eliminated the rivets. There’s just not enough overlapping material so instead they welded the two pieces together across that entire seam. This cleared (more than) enough space to move the radiator forward and mount a clutch fan (likely just for fuel economy). The small brackets riveted to the rear of the crossmember also changed. They got much shorter and the holes are drilled much closer to the crossmember to mount the core support as far forward as possible.
I don’t know much about Cruisers that are much older or younger than my current ’78 so I can’t be certain what you’re facing with a ’74 frame. SOR used to list frame component breakdowns but not so much these days. They do show a 9/71-1/75 core support change and another from 1/75-8/76. This may simply reflect the F to 2F engine change with the post 8/76 change reflecting the addition of the fan clutch. Going on memory here I believe that the welded seam line that Toyota used on the 77 and later crossmembers falls directly through the center of the earlier rivet line. A few options:
1. Cut back the top rear edge of a riveted crossmember to the 77~ dimensions, weld it up, and then re-drill the small core support brackets to move the radiator forward like stock for your year or...
2. Grind back that rear edge of a riveted crossmember as far as needed and the re-drill the core support brackets to get the core support moved forward enough to clear your fan/clutch. I think it’s pretty easy to get another 1” - 1.5” this way. The one I did never had any problems. I think I was able to use stock core support rods or maybe we had to use the 9/71-8/76 ones. Can’t remember.
3. Swap crossmembers with a 77~ one.
HTH. Sorry for the long post.