I'm thinking of buying Wheel Vintiques Magnum 500 wheels for my '69 Mustang.  I'll get the 15x7's with a 4 1/4 backspace.  I currently have drum brakes and will do a disc brake upgrade later.  A couple of people have told me I should get the disc brakes first to ensure good fitment, but going from drum to disc couldn't make that much difference could it?  Has anybody else dealt with this?  

I am not an expert here but I would think with the size of the wheels your going to use it would not make a diffrence. To my knowledge the reason people say do the disc swap first is indeed to make sure the rims you just bought are going to fit with the calipers your going to be useing. I believe the problems are more common in the 14 inch wheels.  

Thanks.  I appreciate your input.  My disc brake upgrade would just be something in the stock range, so I'll bet your right about the fit.  If I was going with some huge, high performance discs then I would probably need to proceed with caution.  Thanks again.  

topdown69
There can be several problems. some disk brake kits make the wheel track wider, some kits will not clear 15 inch wheels. There can be other problems. Do the disk conversion first, then wheels.

Bluemustang