6x137.5
Bolt pattern for a 1985 GMC Sierra Classic 1500 is 6x5.5 (That is what mine is)
6x5.5
8x6.5
6x5.5
5x5
6x5.5
6 x 5.5
six on 5.5 chipc@kovach.net
K1500 is 6-139.7mm/6-5.5"
yes they are
The 2004 GMC Sierra-2500HD has 16 valves.
The 2004 GMC Sierra-1500 has 12 valves.