I'm putting a Comp Cams 286H in my 414. I will be running power brakes. Does anyone have this set up? If so how is the vacuum signal? If I advance the cam 4*(which will be a total of 8* since it comes with 4*)will my vacuum go up or down? My DCR will go up some if I do to around 8.1 graemlins/hurray.gif .

I ran the 286H in my 355 . I used a vac can with the power brakes and it worked great.

Anybody else? What about the second part of my question?

I can't answer your question from experience, but I don't think a 286H will be too much cam for a 414, even if you install it straight up. With that size bore and stroke you should get enough vacuum to run power brakes.

Just looking at 6D9's reply, if a 355 runs fine with that cam and power brakes, a 414 should have no troubles at all.

The reason I ask is the description Comp. Cams has for this cam is,

"286H Magnum™ is a design to fill in the gap between the 280H and 292H. Designed for serious street machines and bracket racers. With a rough idle and lower vacuum signal, this is not an average street cam. At least a 2500 RPM converter must be used, but a 3000 is recommended".

The "LOWER VACUUM SIGNAL" got my attention. I was wondering if advancing the cam would help or I need a vacuum canister to help.

you'll have no vacume problems with that cam, we ran a 292H in my friends 68 camaro with vacume brakes without any problem, hell it made so much torque with the 406 that you could take off in 3rd with his muncie. And the 292 is considerably larger than yours.

It all depends on your compression. My 12.5:1 412ci small block gets 12-13" vacuum even with the 302/312 cam...I can almost run power brakes!

The scr is 10.25:1 DCR is 7.9....8.1 if I andvance the cam 4*.

I wouldn't advance it 4*...as you know it already has 4* advance ground in. Everytime I see someone do this with a 230*+ cam they have no idle vacuum and a seriously ragged idle. I think it puts the cam outside of its operating window when you do that. The last one I seen was my buddys dads 429 ford with 9-1 compression and a 280 magnum cam. He put it in 4* advanced and it wouldn't operate the power brakes hardly at all, and it was definately a fender shaker. Sounded mean as hell but didn't clean up until about 2500 rpms, then it would rip your head off. He changed it to straight up, and it totally changed the way it ran. It pulled better off idle, had a more "appropriate" sounding and acting idle for a cam this size, and the power brakes worked just fine.