No, my cage isn't tagged, and I doubt it would pass Bill Savage's tech. It's all 1 1/2" tube, which I believe I've far exceeded the weight limits on that. I'm comfortable with the design, though...I think it has plenty of tubes and decent triangulation, and all that, but it was originally designed as a chassis stiffening rock crawler cage. If I built it as a racer...lots of things would be different.
I was saying 4700 because next season, there's supposed to be a few more guys racing in 3700 who have built their cars to the rules...Ford motor doesn't really fit well there...but, if the entry numbers are still down...who knows.
-D
I could see the 1.5" being a problem as you said but in all reality I bet it is more then enough.