Ok, so I installed a pressure guage, set fuel delivery at 7 p.s.i.

Adjusted the idle mix to best possible vacuum results and then the timing of the distributor.

Here is the testing results that I need interperted...

Steady flicker between 6 to 6.5 in-Hg

When I rev it, drops close to 0 then while reving 16 in-Hg
when I let go of throttle it jumps to 21 in-Hg then drops to 6-6.5 in-Hg
(normal right?)

however, when I dissconect the accesory line (going to the headlights) and allow the carb to vent to atmosphere, the vaccum guage reads 14.5 in-Hg also the idle seems to clean right up and the rpms increase about 100-150 rpm

71 383.
Casting number g383

fittied with

Holley rh 780 cfm four barrel & Large K&N airfilter

Weilend Team G intake Port size is 2.24" high by 1.15" wide. Manifold height is 4.69" in the front and 5.69" in the rear

Aftermarket Camshaft, connecting rods, pistons during rebuild. Not sure of what these components are. The Cam is agressive

MSD 6AL electonic ignition system with 7000 rpm chip
MSD blaster pack
Accel 9mm wires

 

p.s. I am 1138.45 feet above level so I beleive that 1 in-Hg is to be added to my results

 

do you mean you get a fuel pressure reading of 0 when reving?

 

no, the vacuum

 

note: I did the timing tonight and was able to dial it in at 12.5 idle and 36 total.
Vaccum went up to 8-8.5 inch-hg

 

bump! help

 

We'll talk tomorrow. We havent forgotten you! Meantime, make sure you have a plug or cap to cover everything that comes off the carby or intake, including your booster.

 

Done and done.

I am going to change the carb to manifold gasket this afternoon when it warms up... -5 c right now!

After that I might do the manifold to block gaskets.

Just dont understand why vaccum would go up if I unplug the carb line... I need a good manual on the 3310-1

 

got vacuum up to 9.5 almost steady. still cant explain why vacuum goes up when line connectors are open. One thing I did find was the vacuum advance was open (had no nipple) so I blocked it off. Is that the right thing to do? Or should I have left it open to atmosphere?

B U M P! HELP!

 

Hard to say with out seeing all this happening but just reading your last remark kind of tells me you are way rich on the A/F raito, if your making a vaccum leak and the motor runs better that kind of points you in the direction of the motor in running too rich - hook your vac guage up and play with the mixture screws, your looking for as much vaccum as possable before it starts to stumble and 0 in. when you snap it back up to 21 in. is what you want - plug all vaccume outlets ported or not - what is your cam overlap and are you sure the throttle plate is closed past the main metering transition point?

 

not sure of the overlap. I did not install the cams. I am going to gas her up later and work at it some more. I posted on the holley site and got some more info...

Just got in my front valance, so that goes on first, then I will play with the vacuum...

 

aka -

8.5 with a slight flirt is normal for an "aggressive" cam, but without knowing the exact specs hard to tell. Vacuum leaks can be sneaky, but the only gasket leaks I've hard were the exact opposite, they were pretty noisy. Before you start replacing stuff, get a water spray bottle and squirt water around anything that could be leaking (gaskets, hoses, etc) and listen for changes in sound or rpm.

Archer