Vacuum

[Bob]

How does the wrong camshaft have an effect on vacuum? Ever since I changed mine years ago after the start up there is a hard brake pedal until it runs a few a few minutes.

[Dino]

With a single plane intake, vacuum goes down as overlap goes up.  What cam are you running?

[MSRacing89]

How does the wrong camshaft have an effect on vacuum? Ever since I changed mine years ago after the start up there is a hard brake pedal until it runs a few a few minutes.

Proper Timing, carb tune and idle speed will all maximize vaccum especially when cold.  Vacuum will be at its weakest here, assuming you don't have high idle or choke.

Boosters can fail too, so it might be time to look at that as a possibility.  Summit and others sell a vacuum canister that checks air and keeps it as a reserve.  Good for big cam, low vacuum situations.

[nvrbdn]

just added a vacuum canister for reserve vacuum in my charger after adding the 484 lift purple cam. my brakes sucked before i added the canister. think it was 40 something at performance parts plus.

[fy469rtse]

and in extreme cases like mine , have gone the hydroboost set up as shown on threads on here, canister and vacuum pump set with a switch to gauge for maintaining pressure, still needed vacuum for headlight doors and a/c controls

[Bob]

Took me awhile to find the information: I installed July of 2006.

This is the cam I installed in my 400 4v motor.
Make: Lunati
Lift at valve: in .480  ex.480
Duration: in 230 deg
            ex 230

[fy469rtse]

I woudnt have thought you would have vacuum problems with  that cam, was it dialled in correctly, put a vac gauge on it to see what it pulls

[Bob]

I woudnt have thought you would have vacuum problems with  that cam, was it dialled in correctly, put a vac gauge on it to see what it pulls

Thats what I hope to do Saturday.

Bob