Police Interceptor Heads?

I rebuilt the motor on a 383 4 speed superbird into a stealth 426 (440 crank and rods, custom quench dome pistons, ported big valve heads)
0nly 383 superbird I'd ever seen or heard of and I was at Corta Madera Chrysler Plymouth as Service Manager when they and Hemi Cuda's were on the sales floor, then factory Zone rep.