Mine are 3/4" in front and 3 3/4" in rear but before you go out and start cutting understand that I'm using a 39 car frame (same as pickup thru 41) and a 46 cab. The cab had the gas tank under the seat (sense removed) and that makes the floor pans different than the 40 cabs. I mocked mine up so the cab base cleared the running boards and made a template pattern of the wood pieces from front of cab to rear and cut my own.
Thank you. We are using 40 cabs on 46 Frames We are building two trucks at once and intend to make metal spacers to replace the wood blocks
I don't think you will find a kit for that one. May have to do as I did. It doesn't have to be wood. I'm considering doing mine with plastics.