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Will an LS1 with a Truck Norris NSR cam generate enough vacuum for power brakes

235 Views 6 Replies 3 Participants Last post by  scudzuki
I pulled the 350 SBC out of my 69 vert and I'm wondering if I can pull the vacuum pump the previous owner installed before I put the rad back in. Car has GM discs front and rear (probably doesn't matter) and a 11" brake booster. LS1 going in has a Truck Norris NSR cam and is otherwise stock. Seems like it should have enough vacuum but to my mind it should have had enough with the GM crate 265 HP motor I pulled which also had a mild cam, albeit a stupid one (Comp Camps Thumpr).

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I would have said yes.... until that 107 LSA... now unsure.
My thoughts exactly. That's a lot of overlap. Didn't consider the power brakes when I chose the cam.
Gonna talk to BTR on Tuesday.
Seems a little questionable with the 11" brake booster. The SummitRacing SUM-8728R1 has the same power curve and should provide more vacuum thanks to much less overlap. It will require springs but it's quite a bit less expensive than the BTR, so the cost isn't that much more.

Thanks Mike. Cam is already installed. I also installed LS3 valve springs when I picked up a set for cheap. Maybe I'll look into a hydroboost.
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I only have about 10" of vacuum (110 LSA) and no real issues unless in traffic and on the brake a lot (pedal gets stiff)

I have no idea on that cams vacuum, but IF below 10", could be a problem ?
Maybe a vac. pump would help ?
There's a vacuum pump installed by the previous owner in the car already. Since the radiator is out I was thinking about removing the pump while it's accessible.

Last time I drove the car I noticed the pump did not turn on with the ignition switch in the on position and the brake pedal was very hard. The car was of course difficult to get stopped. It might be an electrical issue (some of the wiring done by the previous owner is pretty lame), and since the pump does not have many hours on it I think it's likely it has not expired.

I'm wondering if a vacuum canister would be a better solution than the pump. When the pump worked it would run out of vacuum if I had to press the brake pedal more than twice within a few seconds. If I can get the pump working again maybe I can extend its usefulness with a canister? Or can I connect the can to the manifold and rev the motor a few times before driving, then normal driving should would keep the canister charged up (charged down?)

Anybody used a canister rather than a pump or in conjunction with a pump?

Thanks. Please keep the ideas coming.

Happy Memorial Day.
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