Will the OEM style 11" booster, actually clear a tall valvecover, on a BB, in a 70' Chevelle? 540 - GM 502 block/AFR heads. I know vc removal would be a problem, but I'd like to get the engine in, then see how the power brakes respond. If not enough vacuum, I'd consider going hydroboost. If vacuum works, I'd downsize to a dual 9" booster. Appreciate the replys.

Here is a pic of a 540 in a 70 Chevelle with a Hydroboost. Lots of clearance. When I had the stock booster in there (dont remember the diameter), it was almost touching the valve cover and, with a low vacuum motor, I had piss poor brakes. If you think you will have a low vacuum condition, dont waste your time with the a vacuum booster. Go hydroboost. Pricey but, how much $$ you got in that 540? You might regret going manual brakes too, but you wont regret a hydroboost. As you can see, the hydroboost is not much bigger than the master.

http://i225.photobucket.com/albums/dd275/70SS540/DSC00227.jpg

Here is a pic of a 540 in a 70 Chevelle with a Hydroboost. Lots of clearance. When I had the stock booster in there (dont remember the diameter), it was almost touching the valve cover and, with a low vacuum motor, I had piss poor brakes. If you think you will have a low vacuum condition, dont waste your time with the a vacuum booster. Go hydroboost. Pricey but, how much $$ you got in that 540? You might regret going manual brakes too, but you wont regret a hydroboost. As you can see, the hydroboost is not much bigger than the master.

http://i225.photobucket.com/albums/dd275/70SS540/DSC00227.jpg

Thanks 70SS540. Judging from your pic, a line lock is compatable with hydroboost. That question had crossed my mind.

yep, line lock works fine.

Hydraboost was too expensive for me. when I stabbed the engine in I had tall valve covers on it and fit under the stock 11" booster, but not by much, in fact I had to loosen it up so I could slide the engine in. Of course these valve covers were the same height all the way around, I'd bet if the fender side of your valve covers were slanted like some it wouldn't be an issue. I never actually ran it with the 11" booster because I was paranoid as to what could happen if I broke a motor mount and it hit the booster in the process... could lead to a scary shutdown I would imagine. Anyway, I bought a 99 dollar 9" GM booster off of the bay and it fit well, just had to grind on one of the lower mounting holes a bit to get it to fit the old bolt pattern... It seems to work fine with my 540, but I have a relatively mild hydraulic grind for a cam.

Here is a pic of them with the 11" booster.
http://project71.net/skeeveman/2007-04-22/IMG_0322.JPG


Here is a pic of how close the covers are to the 9" booster.
http://project71.net/skeeveman/2008-01-19/IMG_0655.JPG


I know that they are different valve cover, but they are essentially the same size when it comes to the height where the booster would hit.
Hope that helps.

Jake ....

Thanks for the pics and info. I'll wait and see how much vacuum, my 540 will produce. Depending on that, ... a smaller booster or if needed, some sort of hydroboost.

Here is a thought........someone is manufacturing the original style BB valve covers in a tall version. It had the dent relief at the rear drivers side for the stock booster. Not sure if they work but worth a search. I will try to find a link and post it.

I used the Crane Cams stamped rockers with the roller tip to utilize the low valve covers on my 502.