[Mike Bradbury]

Yeah it can be confusing with some dimensions in metric and some in imperial. the bolt pattern is 8X165.10mm which is 6.5".

Most after market rims that are custom are lug centric versus hub centric. They do this so that the manufacturer can make wheels that fit various axles. they also over size the hub just slightly because ford has a different size hub than Chevy and Dodge and so on. Chevy 8 lug hubs are generally 4.5" which is 115 mm but generally they size them to 121mm. If you want hub centric wheels with flat lug nuts (not the conical shaped ones then look for wheels with 115mm bore. Alcoa is a good example of wheels that are hub centric.