Al, I remember the pain you went through to get the cuda.
Now you want something else?
If I had looked at 2-3 cars that didn't fit, I'd have measurements memorized!!! How wide at the shoulder, how tall seat to cage, how far pedals to seat back at LEAST!
Seems like you won't be happy until you have a Pro Mod you can just change the seat in and both you and the son can race.

Good luck on the hunt, but building from scratch is going to big time and money.