More info about the front kit:

The front GM A, F, X Body disc brake kit allows an easy solution to convert your drums to disc. Everything included in one kit. The spindles are stock height and will not change the ride height. Your rims need to be 15" or larger or the kit will have clearance issues that you'd have to work around. Disc brake conversions typically create an offsets of 1/4" to 3/8"

About the Wilwood Calipers:

Wilwood#120-10937-RD

D52 Dual Piston Caliper

2" Diameter Pistons

1.28" Rotor Width

Wilwood's D52 caliper is a direct bolt-on 2 piston replacement for the factory original single calipers on many 1968-96 GM Passenger Vehicles and Trucks. Forged billet aluminum bodies, stainless steel pistons, and competition style high-temperature seals put and end to the rust, bore pitting, and seal failures that plague the OE caliper design. D52 brake calipers provide low-maintenance performance and a huge weight savings with high temperature reliability for the street and track.

D52 performance brake calipers mount in the stock location over stock rotors, use the original style OE D52 brake pads and an OE banjo bolt brake line. mounting. Calipers can be used with most wheels that clear the OE calipers. The Rear calipers with 1.25" piston provide 2.46 cubic inches of piston area per caliper, to maintain the original front to rear brake bias and use of the OE master cylinder.