Doing a LS swap in a 69 camaro with power brakes and just looking to see if anyone has any vacuum readings for their LS1 5.7 running a Torquer V2 or V4 cam? Making sure I'll have enough vac for power brakes with my cam choice. Guessing this would be somewhere in the 11-13 range. Seems like the boosters in the newer cars aren't as sensitive to lower vac as what might be found in a old car with original booster or even aftermarket.

Please note what LSA your cam is on if possible. thx.

 

My newest cam is a solid roller 239/247 with 17* overlap at cold idle.

Your brakes will be fine so long as they are in perfect working order already and consist of a proper combination of booster and master cylinder size.

Either of those cams (or really most aftermarket cams) will need a higher than stock stall torque converter if you are not aware of that.

 

My carb'ed Maverick has a 113° Torquer II on a fairly stock 346", it pulls 14" at 900 RPM. If I idle it down to 750, the vacuum falls to 8", so a lot will depends on your idle speed...

 

I have mine set to 850rpm in park/n and 900 in gear.

 

buy the cam you want for power. If you need it, buy an external vacuum canister for your brakes.

 

Yeah - tried the vacuum can on an LS1 with a Trex cam - didn't help at all. Would have had to go with hydroboost brake system.

 

I've got a vacuum canister on my turbo'ed S-10 and it'll hold vacuum for several days. In this pic you can follow the hose from the top of the throttle body block, thru a check valve, to a "tee" at the brake booster, then on to the vacuum can on the DR side fenderwell. With it plumbed like this, you build vacuum on coast and because of the check valve, it stays in the can until you use it. In fact, even with the engine off, I can get several good pumps on the brakes...