Disc conversion issues - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Longhorn 70 · 12-13-2012, 07:47 PM

I have received a disc brake conversion kit for my Longhorn. Upon inspection I see the lugs on the discs are much larger diameter. Are 72's 9/16"? I have a line kit, dist valve kit and new master cylinder/booster on the way too.

I can hardly wait for more issues to arise. Anything I should look out for?

**FirstOwner69** · 12-13-2012, 10:32 PM

Yes, 71s and 72s were 9/16". Earlier w/drums were 1/2".

davepl · 12-13-2012, 10:35 PM

Yep. I did this on my '70 and wound up replacing all the studs up front with the 9/16" that they came with (off a 72) and converting my rear Dana60 to 9/16 also, which started life as 1/2" studs.

I suppose you could run mismatched studs (9/16 up front and 1/2 in the rear), but I wanted to get them all the same size.

rico7769 · 12-13-2012, 10:46 PM

good info. Prob going to order the same set for my 67 sometime next year

Longhorn 70 · 12-14-2012, 09:29 AM

Thanks davepl. Was the rear stud change difficult? Or was it pound the 1/2"s out and press in 9/16"s in the drums? Heck maybe I'll do a rear disc too. They are about $500 from BlackBird.

12-13-2012, 07:47 PM	#1
Longhorn 70 Registered User Join Date: Dec 2012 Location: Chandler AZ Posts: 1,149	Disc conversion issues I have received a disc brake conversion kit for my Longhorn. Upon inspection I see the lugs on the discs are much larger diameter. Are 72's 9/16"? I have a line kit, dist valve kit and new master cylinder/booster on the way too. I can hardly wait for more issues to arise. Anything I should look out for? __________________ 1970 Longhorn, Front Disc, 350/4 bolt, 882 heads, HEI, Edelbrock, 700R4, HO-52/4.11. 1996 Corvette, Collector Roadster, LT4, 396, 450RWHP, 6sp, 4.11/Dana44/posi 5 point roll bar And let us not grow weary of doing good, for in due season we will reap, if we do not give up. Gal 6:9

12-13-2012, 10:32 PM	#2
FirstOwner69 Senior Member Join Date: May 2010 Location: Wisconsin & Arizona Posts: 4,853	Re: Disc conversion issues Yes, 71s and 72s were 9/16". Earlier w/drums were 1/2".

12-13-2012, 10:35 PM	#3
davepl Registered User Join Date: Aug 2006 Location: Redmond, WA Posts: 6,334	Re: Disc conversion issues Yep. I did this on my '70 and wound up replacing all the studs up front with the 9/16" that they came with (off a 72) and converting my rear Dana60 to 9/16 also, which started life as 1/2" studs. I suppose you could run mismatched studs (9/16 up front and 1/2 in the rear), but I wanted to get them all the same size. __________________ 1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible

12-13-2012, 10:46 PM	#4
rico7769 Hybrid67 Join Date: Jan 2009 Location: Martinez, GA Posts: 195	Re: Disc conversion issues good info. Prob going to order the same set for my 67 sometime next year __________________ Keep em' Running! All show.....no go

12-14-2012, 09:29 AM	#5
Longhorn 70 Registered User Join Date: Dec 2012 Location: Chandler AZ Posts: 1,149	Re: Disc conversion issues Thanks davepl. Was the rear stud change difficult? Or was it pound the 1/2"s out and press in 9/16"s in the drums? Heck maybe I'll do a rear disc too. They are about $500 from BlackBird. __________________ 1970 Longhorn, Front Disc, 350/4 bolt, 882 heads, HEI, Edelbrock, 700R4, HO-52/4.11. 1996 Corvette, Collector Roadster, LT4, 396, 450RWHP, 6sp, 4.11/Dana44/posi 5 point roll bar And let us not grow weary of doing good, for in due season we will reap, if we do not give up. Gal 6:9



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