Booster pressure question

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69swinger340

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Hi Gang,
I converted the fronts from drum to disc using SSBC conversion kit for 69 Dart, including a power booster. I put an oversized comp cam in the 340 and am not making enough vacuum pressure at idle to effectively power the booster. The booster works fine as rpm increases. I've heard some anecdotal remedies (reservoir, etc.) and have an email to SSBC tech looking for a solution. Any suggestions?
Thanks!
 
I put a vacuum reservoir from Summit on my 350 Malibu. 10.5 comp, .513 lift, 300 duration with 1.7 rollers.
Made a big difference.
 
Years back, I put in Rhoads lifters, that would bleed down at lower RPMs and allow the vacuum to build...it's a crutch.
 
Hi George,
Check valve looks good, had it checked at the shop that did my front end this week. The car brakes normally going down the road but brakes hard when sitting at idle, strange, as I would expect it to be opposite to that according to my understanding of how vacuum pressure is created. I have no previous experience with this type of thing as I'm new to the mechanical world. Eager to learn though. BTW: I'll pm you about a possible visit tomorrow?
Jim
 
I believe SSBC sells a vacuum pump. How big is the cam ?

Thanks for the reply Adam, here are the specs on the Comp Cam.
Hydraulic - strong torque and throttle response, 2200+ stall.
Comp P/N: 20-224-4
Cam grind number: XE274H
RPM Operating Range: 1800 to 6000
Duration: in: 274 ex: 286
Lift: in: 488 ex: 491
 
Hi George,
Check valve looks good, had it checked at the shop that did my front end this week. The car brakes normally going down the road but brakes hard when sitting at idle, strange, as I would expect it to be opposite to that according to my understanding of how vacuum pressure is created. I have no previous experience with this type of thing as I'm new to the mechanical world. Eager to learn though. BTW: I'll pm you about a possible visit tomorrow?
Jim
Sounds like a simple case of low vacuum buddy.
I'll be at the Southbury Training School show tomorrow. Maybe next week??

George
Iwouldlovetoseethecar :D
 
You may be able to fix it on the cheap by yanking a vacuum pump out of a 4-cylinder Chevy Cavalier. There are probably a bunch of other small-engined cars that have them aside from that.
 
You may be able to fix it on the cheap by yanking a vacuum pump out of a 4-cylinder Chevy Cavalier. There are probably a bunch of other small-engined cars that have them aside from that.

Sounds like a viable alternative. SSBC wants 395.00 plus tax for their booster kit. What it amounts to is an electric air pump that has to be mounted and wired. The intake gets capped and the pump does all the work. Not quite ready to spend that kind of money. Thanks for the suggestion.
Jim.
 
another work around/crutch solution is a vacuum canister(just a big tomato juice can) with one way valve. I used to see them on mid 80's Fords, not sure what their purpose was on them.
 
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