does anyone have a link or links for sites that has rims and tires???? im looking at getting some toyo proxies and need to figure out what size of tire and rim would be best for me thanks:)

Try these:

http://www.rims-n-tires.com/rt_specs.jsp

http://www.discounttiredirect.com/direct/brochure/info/tmpInfoTireMathNS.jsp

The OEM wheels on a 2500HD are 16" x 6.5" with 4.875" backspace (28 - 29 mm offset)