[GCncsuHD]

Yea, the spacers with the wheel studs in the spacer are what you want. I don't trust the slip on spacers much at all any thicker than 1/4". I have ran the bolt on style in 1.5", 2", and 2.5" on 3/4 and 1 ton trucks towing heavy loads with no issues, just make sure to torque them down properly, drive for a day or so, remove the wheel and recheck the torque on the spacer and you will be good.

And yes the 1.25" is the distance pushed away from the hub...Stock wheels of that era used around a 3.5-3.75" backspacing if I remember right, the newer stuff uses anywhere from 5-6" of backspacing depending on the exact application. By using a 1.25" spacer on a wheel with 5" backspacing you effectively make a 3.75" backspaced wheel. Of course you will have to get the wheels you want then measure to get the right size spacer.

Also, the late model 88+ 6 lug stuff has a smaller hub diameter that might not fit over your hubs, but since the backspacing is off too, using the spacers will eliminate the hub interference.