The power brake booster on my 66 El Cam has sprung a leak. Is there a more powerful one that will bolt on? I have power drum brakes.

Maybe try one from a Cadillac or another heavy car....

Well, I used one from a 96 1/2 ton 2wd Suburban, I drilled out the rivets on the orig. Chevelle booster & took the brackets off. I slotted the bolt holes about 1/2 inch closer together & bolted them to the new booster. I also had to modify the pushrods. Now is stops like a luxury car.