What year Chevy S-10 frame will fit under a 1946 international half ton cab?

There's no single Chevy S-10 frame year that's a guaranteed, bolt-in fit under a 1946 International half-ton cab. The frame dimensions and mounting points are significantly different between those two vehicles.

Any such swap would require extensive fabrication and modification. You'd need to:

* Modify the S-10 frame: This will likely involve cutting, lengthening, or shortening sections to match the International's wheelbase and body mounts.

* Fabricate new motor mounts: The International's engine won't line up with the S-10 frame's motor mounts.

* Create custom body mounts: The International's cab won't mount directly to the S-10 frame. New mounts would need to be designed and welded.

* Address the suspension: The S-10 suspension will need to be adapted to work with the International's body weight and dimensions.

While any year S-10 frame *could* be *used* as a basis, the effort required will be immense regardless of the year chosen. The overall width, wheelbase, and suspension geometry are major hurdles. It's a significant custom fabrication project suitable only for experienced mechanics and welders with access to specialized tools and equipment.