After getting help on this forum about using a 8 inch dual diaphram booster and electric pump, I decided its time to order the electric vacuum pump
I called several places and some sell ones that use a diaphram and others use a piston. Questions are
1. which is better diaphram or piston pump.
2. MPbrakes sells the piston which they claim is better, but shuts off at 18". Is that enough vacuum for a 69 with a big block and stock front discs and rear drums ?
3. What is the proper M/C bore size for an 8 inch power booster ?
Thanks

[ 04-18-2003, 05:52 PM: Message edited by: vmdb ]

The pump that we sell is setup to turn on at 15" and shut off at 23". Personally I think its much better espically since you are running a 8" dual, whenever I sell that booster I always reccomend around 20" vacuum, it does suck up alot!!!

Matt

I've seen 18 in online advertisements as the minimum. I get 10-11 inchs vacume at low idle and cruise with good brakes just the same but keep the idle up a little above normal. I'd figure what evers rebuildable cheap instead of buy another possibly $300 pump. I'd think a diaphram pump might fit that requirement if it's openable.

some people here are using the hydroboost setup,and others are using the ? '77? Malibu non power assist master cylinders.those options might be cheaper for you.

i have a '67 that came factory front disc,Not power disc,
i replaced the 4 piston stuff with '69 style single piston setup,and kept the 1967 non power master cylinder,and am quite happy with
the pedal effort,stopping ability.
But,i learned to drive in old vehicles,and also drive various equipment in my job,so i have no problem adjusting to different brakes,in different
vehicles,wether a front end loader,a dump truck,or a '67 Camaro,etc. ;) good luck, do a search on master cylinder,it may give you more ideas. graemlins/beers.gif

Matt, is yours diaphram or piston, how much is it and do you have either a photo or a website to see it ?