UPGRADE BRAKES on a 79 K25

Hello, my first post except for my introduction. yippie.

Is it possible to find larger rotors and matching calipers for my 1979 K25? If so who can supply them?
I like a semi soft pad that doesn't last for 100,000, 20,000 is fine. Any suggestions? What brake pads have you had good success with?

With larger rotors, matching calipers & brackets, you may need a larger size wheel & tire combo.

Why? You're poking a sleeping bear. Yes, some folks like to "upgrade" brakes, but the original ones [maintained] are just fine. There are ways to increase stopping power such as different lining material and rear cylinder size. I own a K 20 SB used as a wrecker for over 300k miles. Truck weighs 6k, figure the average car is in the area of 3500 lbs plus. Although I would not rally it the brakes never failed or overheated.

So you upgrade the fronts,now the front/rear bias is wrong. And the master cylinder and combination valve wasn't designed for your combination. I'd leave things alone,buy EVERYTHING off a truck with bigger brakes or discuss your situation with an engineer that specializes in brakes,and has no interest in selling you anything. The engineers that designed your brakes,took a whole lot of things into account,situations we never thought of and designed a brake system accordingly. Years ago I put different rear calipers on my DD it stopped so much better.,I am a genius!. I was driving to work on cold drizzly morning had to hit the brakes quick in a lane change,the car went completely sideways,hand over hand on the wheel,it was completly sideways again. I was lucky I didn't hit anything and no one hit me.90 percent certain it would have been a fatality. But my better rear calipers sure stop great in ideal conditions.

I believe there are a couple options for "direct replacement" aftermarket, dual piston calipers. Wilwood and another company too I think. There are oodles of different pad compounds available from various companies.

Front/rear bias can be adjusted with an inline valve, if needed.

Wilwood offers a front and rear caliper, just so you're aware. They have options for both the 70's and 80's calipers, all that's different really is the brake line thread on the caliper. 70's is sae 80's is metric.

I believe they offer single piston and dual piston. I have a dual piston rear kit, just haven't got a set of front calipers yet.

Wilwood has it figured out. The rear calipers have smaller pistons, so less braking power than their front calipers, so they should be set up pretty good factory, but then dial it in with their adjustable prop valve.

The reason why rear disc brake kits suck is because you're using front calipers on the rear and then no one changes the prop valve or anything else. I opted for the willwood master and prop valve and calipers because all the stock replacement stuff is junk.

If you wanted to keep stuff factory, the wilwood prop valve is only like $100 dollars. I would modify my lines to put that prop valve in, over getting a standard replacement that are nothing but trouble.

For a parking brake I'm opting for a mechanical driveline brake. It'll be a little spendy, but it'll actually work, and work very well. Wilwood also offers a driveline brake kit for an np205.