power break booster?

[philB]

want to add power break booster on my '69 c10 stepside w/sbc auto,looking at adds, differant sizes to choose, 7,8 9" single or duel diap., what will fit without too much trouble and give better breaking over the drum/drum oem, replaced all the breaks and hardware, does ok but like to add the p/booster, engine has good vac at idle, 20" mid teens crusing, have a new m/cylinder for the d/d on now and can that be used with p/booster or have to have new one, this is a great site for info without going thru the try and buy thing over and over.