[1quiknova]

On my 350 I hooked up a vaccum guage when i adjsuted my carb and noticed that it read at 15, steady. They say and engine should pull between 17-21, and says that it is a valve timing issue. I just built the motor, and the cam is in right, I know for a fact, I even double checked by making sure each valve on #1 was clsoed at TDC, what could be causing this problem?

[DoubleVision]

there may not be a problem, is the cam stock? if it`s stock it`ll read around 20 or so, if it`s a performance grind it`ll read lower. low spark timing can cause low vacuum readings, excessive slack in the timing chain will alter the valve timing events and will also effect vacuum, as will vacuum leaks, high idle, etc.

[1quiknova]

Now that i think about it, it was idleing around 1000 when i checked it, i then bumped the idle down to around 800, and yes it is a comp 274 w/ .490 lift and like 236 duration at .050. I also jsut have a stock HEI with lighter springs and a stock style coil and wires, but the wires checked out as far as resistance went at like 2,000 ohms, and the plugs are gapped too much, like .55, shouldn't they be at like .35? Should i upgrade to better wires and a high voltage coil? I can get pertronix stuff at cost so that's not a problem

[DoubleVision]

I`d just run the plug gap at .045, and yes, a ignition upgrade with spiral core wires along with a matching coil and module is always a good idea, but it won`t help vacuum any. with the cam your running your lucky it has 15 inches. My 350 has a crane cam with 210, 216 duration and it only pulls 15 inches at 800 rpm. If memorey serves me right the overlap figure is what effects vacuum, but don`t quote me on that.

[bracketeer]

My last 350 had a Comp 268H with the perf/rpm package and I only pulled 8 inches of vacuum.

[1quiknova]

cool, sounds good, yea, i have a 274 with the performer rpm and vortech heads, it runds great, but i haven't really cracked it yet since i only got about 15 miles o nthe motor, i figured i'll give it at least 500 before I beat on it. I was jsut worried when i saw that the guage said 15 and in the red it said valve timing. But that makes sense b/c i've ehard of plenty of guys only pulling 8