Any idea what the effective piston area is on the Vipers compared to the 2.75" stock calipers?
Not sure off the top of my head. I'll have to go measure them. The viper units do use a staggared piston arrangement with the leading piston being larger than the trailing pistons.
hp2 that sounds great i'm very interested...what else will i need to get them up and running on my 73 up drum knuckles off an a body? are the calipers the red "viper' ones? again i'm very interested!
You would need hoses, rotors, bearings, grease caps, and master cylinder. All the first generation calipers are black. Some say RT10, some say Viper. You can have them refinished by a rebuilder in red, yellow, silver, or other colors. I do have a divorced style, lightweight master cylinder and adapter too if you're interested.
Photo comparison of the Viper, Wilwood, and stock calipers below.