It's been a few years but back in January 2022 I was able to get the Flathead Ford running perfectly with the 7747 using the AT28C64 chip. My programmer worked 100% and I ended up making 29 changes to the tables before getting it running nicely. I'm back working on the truck and making the final wiring harness.

Wanted to update this thread in case anyone else is looking for a chip option for the 7747.

Cheers