70 to72 chevelle wheels for disc brakes are 14 by 5 inches .wide 73to 77 with 14 inch are 6 wide .some came with 15 by 6 wide , rally wheels can be 6 or 7 inches wide .THE SAME IS TRUE FOR CUTLAS LEMAN CENTURY WHEELS .MONTE CARLO HAD 15 BY 6 ON MOST EXCEPT RALLYS WERE 15 X 7. THE BEST WAY TO TELL A DISC WHEEL IS ON TH BACK SIDE BETWEEN THE BEAD AND CENTER OF THE WHEEL IS FLAT UNTIL THE DIP .A DRUM WHEEL THE RING PORTION GOES IN AND IS SLANTED AT A 45 DEGREE ANGLE AND HITS THE CALIPER ON THAT ANGLE. THE 78 TO 87 INTERMEDIATE WHEELS WILL BOLT ON ALSO BUT HAVE A DIFFERENT OFFSET ,THIS APPLICATION MAYNOT WORK WITH ALL DISC CONVERSIONS BUT WILL GIVE YOU A GOOD START.WHEN IN DOUBT BUY A SINGLE WHEEL AND TRY IT ,OR IF CONVERSION IS NOT INSTALLED TAKE TO A AUTO RECYCLER AND TRY FIT. MOST WILL WORK WITH YOU IF THEY KNOW YOUR PROBLEM.