Just built a 396 sbc for my 81 and never crossed my mind about the vacume needed to work everything. a freind told me my cam was to big i told him you can never have one to big but my gvl is i.571 e.577 is this going to be a problem or is their a solution another way. Any info would be nice.

its not the lift , its the duration thats creates the vac issue..you need at least 11-12 in hg for power brake booster...if you don t have enough, its simple to remedy.. do what I did, get an electric vacuum pump to run brakes,,, http://www.summitracing.com/parts/SSB-28146/ problem solved, it keeps a constant 18in hg in booster

its not the lift , its the duration thats creates the vac issue..you need at least 11-12 in hg for power brake booster...if you don t have enough, its simple to remedy.. do what I did, get an electric vacuum pump to run brakes,,, http://www.summitracing.com/parts/SSB-28146/ problem solved, it keeps a constant 18in hg in booster

The Buick GN Turbo cars used a setup similar to that and it worked great.

It really does work great..money well spent as I had "No Brakes" with only 7-8 inhg with my big roller cam..Also runs my headlights..

Install a positive displacement blower and plumb vacuum to the carb side. You'll have plenty of vacuum.

Install a positive displacement blower and plumb vacuum to the carb side. You'll have plenty of vacuum.
might cost just a bit more, tho.