Greetings from San Diego!

Why do you feel you need to upgrade the power booster? Is yours not working?

Welcome to GMSB from Virginia

Welcome to the site.

The truck is heavy with the camper. I have not yet broken in the new pads and shoes to try a high speed panic stop. Normal braking doesn't feel real impressive. I am not sure what to expect with this truck. The booster is the only part of the braking system I have not replaced so it seems like a fresh start wouldn't be a bad idea. I read somewhere that a "bigger"booster would improve performance.

Boosters reduce effort you apply to the brakes, to increase pressure you need different master cylinder.. Before you go there are you sure you got all the air out of the lines?

Welcome from the Texas Panhandle.

A factory size booster with no leaks should work fine, assuming the rest of the system is in good shape. A larger booster could make for overly sensitive brakes. I don't know about the Blazer, but 3/4 ton trucks had different brakes than 1/2 ton trucks. Discs were thicker to better dissipate heat, and rear drums were larger with more shoe surface area. Next step up was hydroboost.

Did you machine the rear drums or buy new ones? If machined, the fresh surface will have a larger radius "arc" than new shoes, meaning only the center third of the shoes will contact the drum surface.

So many other things to check.

Proper bleeding to remove all air from the lines, as mentioned above.
Condition of hoses.
Kinks in the hard lines.
Stuck combination valve. (Rare)
Good manifold vacuum source.
Calipers and rear brake cylinders installed on correct side with bleed screws facing up. (Don't laugh!)

Did you drive the truck before you started the project? How did the brakes work then? Are they now better, worse, or the same?

Welcome to gmsb. Way cool to see you have a chalet!!!!

Welcome

Thanks to all for the warm welcome!

The brakes worked poorly before I serviced them.
The fronts appeared to be only putting pressure on one side of the rotor. The rears were a mess with stuck wheel cylinders and other issues.
The original drums and new rotors were machined.
New Shoes, wheei cylinders, spring kits, pads, R/B Calipers, Valve, SS lines and hoses installed. I hate to admit I put over a gallon of brake fluid through the New system trying to vacuum bleed It before realizing the first replacement master cylinder was bad. Bought a pressure bleeder and swapped in another MC and now the pedal feels solid. I was asking about the booster because it is the last old part left. I really have not driven much as I need to pass smog first.

Any suggestions on good, reasonably priced cap, rotor, wires & plugs?

Thanks again,
Pete

Welcome. I used mostly Napa parts for my tune up.

One thing to look at before you smog is all the vacuum lines of the emissions system. Mine were dried out and causing a lot of vacuum leaks. I replaced all the hoses and the ported vacuum switches. I also found the vacuum pod for the snorkel on the air cleaner was bad and had to replace it.

Have them pre-test so you don't fail and have the truck listed as a Gross Polluter.