The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Got some new wheels: Boss 338's in 20x10 and 20x8.5

chuckmc8 · 07-13-2009, 09:59 AM

I think that I know whats going on here with the rotors. After 1988 all 5x5 rotors are 'stepped' on the hub like the Astro van rotors that I posted the pics above. i just looked up 88 & up applications for C/10, Van, burb and so on and all are stepped. prior years are not.
So the kwestion (my kue doesnt work on my keyboard) is there a way to run the later model rotors (88 & later) (ed:I have since found out there isnt)
I am running an 1986 crossmember with 2 1/2" drop spindles.

BTW, The coys dont fit w/o mods either. Here is a thread for reading with good photos on the coys. The 71-87 rotor hubs are the problem...after 88 I beleive the BOSS 338 or the Coys just bolt on w/o any mods
http://67-72chevytrucks.com/vboard/s...d.php?t=300737

UPDATE-I went to AutoZone and asked them to put an 86 rotor and a 88 rotor on the bench so that I could compare them- the 88 and later hub (and thus the spindle) is 1" shorter than the 87 & earlier stuff. That explains how the BOSS center cap clips in as designed. There would be ample room on the 88 and up rotor.
here is a 1988 & up rotor

The only other thing to check is if 88 & up spindles (with these smaller rotors & brake components)
would work on 67-72 suspensions.....if not, the grinding/lathe turning proceedure will be the only way to run these wheels.
Maybe useless info, but it doesnt cost anything to gather......and maybe help someone else

07-13-2009, 09:59 AM	#74
chuckmc8 It's alsways something..... Join Date: Nov 2008 Location: Douglasville GA Posts: 1,171	Re: Got some new wheels: Boss 338's in 20x10 and 20x8.5 I think that I know whats going on here with the rotors. After 1988 all 5x5 rotors are 'stepped' on the hub like the Astro van rotors that I posted the pics above. i just looked up 88 & up applications for C/10, Van, burb and so on and all are stepped. prior years are not. So the kwestion (my kue doesnt work on my keyboard) is there a way to run the later model rotors (88 & later) (ed:I have since found out there isnt) I am running an 1986 crossmember with 2 1/2" drop spindles. BTW, The coys dont fit w/o mods either. Here is a thread for reading with good photos on the coys. The 71-87 rotor hubs are the problem...after 88 I beleive the BOSS 338 or the Coys just bolt on w/o any mods http://67-72chevytrucks.com/vboard/s...d.php?t=300737 UPDATE-I went to AutoZone and asked them to put an 86 rotor and a 88 rotor on the bench so that I could compare them- the 88 and later hub (and thus the spindle) is 1" shorter than the 87 & earlier stuff. That explains how the BOSS center cap clips in as designed. There would be ample room on the 88 and up rotor. here is a 1988 & up rotor The only other thing to check is if 88 & up spindles (with these smaller rotors & brake components) would work on 67-72 suspensions.....if not, the grinding/lathe turning proceedure will be the only way to run these wheels. Maybe useless info, but it doesnt cost anything to gather......and maybe help someone else Attached Images Last edited by chuckmc8; 07-13-2009 at 11:42 AM.