Low vaccum???

[coronet69swede]

Hi guys.
Think i messed up in my build.
505 stroker
source heads ported race seats
victor intake
edel 750 carb
flat top pistons
11,5:1 or 8.44DC
Hughes cam 0.05=258/264 0.576/o.592
lobe sep 108 installed 105

vaccum 800rpm is 6inchM and thats the best i get fiddeling around the timing
and carb.

NOT god for my vaccum dist and brakes.
Is it tha cam thats the problem.
Where to go from here.

Johan

 

[ozonedepletion]

I have an external electric vacume pump on mine and it works well hooked up straight to the booster. You can get one off a small japanese diesel truck

 

[BuckNeccid]

x2 on the electric pump. It won't help on your distributor, but it will operate your brakes fine.

 

[65-440]

Your vacuum is normal, get rid of that vac advance !

 

[Stumper]

I'm surprised you can idle at 800 rpm, let along get 6" of vacuum.... While not a "huge" cam that one is fairly stout and couple it with a single plenum Victor intake I'm inclined to say 6" at that rpm is not bad at 800 rpm. You can set the idle up a bit (1000 rpm) to get more vacuum at idle to help with the brakes. Otherwise I would say you need a smaller cam (assuming you have verified no leaks etc.)
I run a 278/286 duration @ 0.05”, 106 lobe separation and .636/.636 lift (.674" with 1.6 rockers) and I can't even idle below 1200 rpm and my vacuum is around 4-5" at idle. If I could get to 800 rpm I'm sure there wouldn't be any vacuum at all

 

[coronet69swede]

Just what i thought. My Bad......but it feels like ithe engine wake up at WOT.

Would it help with a 2plane manifold or is it not worth. New cam is the best
alternative or only if i want vaccum????Will look for a electric pump for the booster and thinking about an ECU for the ignition.

Thanks for the input so far..

god night for me.

 

[Stumper]

I think a smaller cam is the only option if you need the vacuum. I would try bumping the idle up a bit first to see what you get. 1000 rpm is not very high and it might make the difference.

 

[coronet69swede]

I will try that of course.:icon_mrgreen:
Thanks