can someone explain to me what -manifold vac means (on my dyno sheet) here's the list from 4000-6000
-0.6
-0.7
-0.7
-0.8
-0.8
-0.8
-0.9
-1
-1
-1
-1
-1.1
-1.1
-1.1
-1.2
-1.3
-1.3
-1.3
-1.3
-1.3
-1.3
-1.3

On another pull it showed 0.00 on all RPM's.... what does this mean?

It means there was little or no restriction by the carb. In other words, the carb is big enough.... in it's current tune.

I'm sorry, the 0.00 means there is no restriction but the -#'s mean that there IS a restriction? The reason I'm asking is that the 0.00's were with a 1025 Holley HP (not mine) and the -#'s were with my 850 Demon. thanks TJC.

The 0.00 sounds more like the data channel was disabled. The 850 demon pulled 1.3" of vacuum, so it was a slight restriction. Some negative pressure is desirable, to promote velocity in the intake.

cool thanks!

You like to see vacuum below 1". Above 1" means there is a restriction. 0.00" means no vacuum at all so no signal to the carb and no fuel flow. I agree with TJC, that channel was disabled. What the lower vacuum limit is, I'm not sure but I'd guess you'd want at least 1/2".

How does carb jetting effect this number? I was looking at some of the other pulls and as we increased jetting the Torque kept increasing (HP fell off slightly) and the man vac kept dropping.... However, the BSFC was in the .6x range which means I was rich right? But again, the more we jetted it up the more TQ it made....

Can someone tell me a good book to read to clear some of this stuff up?