Has anyone done a rear disc conversion on an 8-lug?

[k2rm]

This is the one I bought. It is universal fit.

http://www.summitracing.com/parts/wi...556p/overview/

It is the 1 1/8 bore which works great with the dual 9" booster. You may need a smaller bore size if you have a different booster or have manual brakes.

It also comes in powdercoated black or unpolished. The only reason I went with the Wilwood master was because I was tired of the leaky caps on the stock units. The Wilwood is screwed down and I have never had a leak. The GM master worked just fine otherwise.

This is the adjustable proportioning valve:
http://www.summitracing.com/parts/wi...1179/overview/

I mispoke about the 5 lb residual valve. It was the 10 lb valve. I installed it near the frame rail.
http://www.summitracing.com/parts/wi...3279/overview/

[swamp rat]

This turned out to be a real good thread! Plus i got honorable mention LOL!

[c20pickup]

yeah I have the power brakes, how do I tell how big my booster is? you said yours is 9 inch, how do I measure mine?

[k2rm]

The diameter is 9". I can't remember the exact depth, but it is probably about 7-8 inches deep.

I believe all C20s with power brakes came with dual 9" boosters, at least my 70 did. Here is a picture for replacement 1970 C20 booster. They say the diaphram is 8 3/4"
http://www.napaonline.com/Catalog/Ca...011_0136007703

Also, depending on your year, you may need to increase the lug size of your hubs. 70 and earlier trucks have 1/2" lugs while the newer trucks have 9/16" lugs. The kits, because they are using front rotors from newer K20s, will require 9/16" lugs. I had to have my hubs drilled out and then I had to find the proper size lug studs to work.

[c20pickup]

Originally Posted by k2rm

The diameter is 9". I can't remember the exact depth, but it is probably about 7-8 inches deep.

I believe all C20s with power brakes came with dual 9" boosters, at least my 70 did. Here is a picture for replacement 1970 C20 booster. They say the diaphram is 8 3/4"
http://www.napaonline.com/Catalog/Ca...011_0136007703

Also, depending on your year, you may need to increase the lug size of your hubs. 70 and earlier trucks have 1/2" lugs while the newer trucks have 9/16" lugs. The kits, because they are using front rotors from newer K20s, will require 9/16" lugs. I had to have my hubs drilled out and then I had to find the proper size lug studs to work.

thanks man! you've been a great help, good to have members like you! expect to hear from me in the future bugging you with questions when I decide to pull the trigger on the discs

[k2rm]

Glad to help! I was only able to dothe job a few years ago due to all of the info I learned here and other forums, so it is great to pay it forward.

[72MARIO]

I also have Blackbirds disk brake kit. its on a Dana 60 I ran into the stud size problem had to drill out the hub to accept the bigger studs I think 67-70 have the small stud hubs. I have 54,000 miles on my truck now Still on the original pads and caddy calipers. I actually use my truck daily always loaded with 2000-4000lbs in the bed daily.
Cheap way to rebuild rear brakes! Just had to buy a drum for my 1990 2500 burb it was $185 Should have bought the kit for it too

[my67c20]

Did it, done it, and love it. Found out real quick that my bench seat adjustment arm was not working. Still have the disk / drum master cylinder and prop valve, but stops like a charm. The e-brake was pissing me off for some time until i actually learned that to set it i had to have my foot on the brake, but otherwise holds great. See this post for more info;

http://67-72chevytrucks.com/vboard/s...d.php?t=495913

Heck your just right down the road if you want to look at what i have done.