does anyone know if someone makes the magnum 500 style rims in 15 x 8? not looking for chrome ones want ones that I can put a trim ring on to match my 14" magnums up front

Depends if by "chrome ones", you mean chrome spokes or chrome rim. The '68 and back had chrome spokes and rim, so we know you do not want that style.

The '69/early 70's had chrome spokes with painted rim. Specialty Wheels makes those in 15x8.

If the '69/70's chrome spokes/painted rim are the chrome ones you do not want, then you are looking for the mid/late '70's style with silver/argent painted spokes and painted rim. I am not aware of those being made in 15x8.

http://www.specialtywheel.com/product-showcase/mopar/chrysler-road-wheel.html

15 x 8 Magnum 500's are available, the problem is finding a trim ring that fits without leaving a gap. One option I have heard of, would be to custom order them with backspacing to match the 15 x 7 trim rings that are available on the market.

want to put on my 73 RR but I currently have the factory 14" magnums on it now but want to put a bigger tire on the back

http://themopardude.com/New_Custom_2.html

This guy does custom backspacing

15 X 8 on my rears with no ring...looks a ton better without ring IMO..