okay..  I got my new intake today for my truck..  replaced it..  (took a little under two hours, would have been quicker but i spent 15 minutes looking for a pipe thread plug)

cranked it..  the extender tube for the oil sender broke at some point in the process..  replaced it..  cranked it up..  couldnt find my trusty vaccum gauge to retime it

grabbed my timing light just to get it close..  set it to 15 deg advance, then drove over to my friends house to pick up the vac gauge i loaned him.  ran like a gutless wonder the whole way..  and got very hot. 

hooked up the vac gauge..  got 12 lbs...  this thing has a stock cam so i knew this wasnt right...  timed it to peak..  19 lbs..  and now it runs like a scalded dog.

put the light on it just for fun..  it says im running 30 deg initial time..

POS needs to be recalibrated and its only about two years old.  I hate timing lights.  This is why I NEVER use them to time a car if I am able to use a vac gauge.

even if your vac gauge shows the wrong figure..  doesnt matter as long as you can find a peak..

btw..  just went back down to retune again..  decided to recheck idle mix with new intake..

got the vac up to 19.5 from about 18.75 at idle..  so it made a difference.. 

 Ben, when were kids we use to set our timing by ear to the highest RPM.When you use a vacuum gauge do you hook it direct on the intake or a port on the carb?. Your talking vacuum at idle.I'm gonna try it and compare it to a timing light,and see which way runs better. 

  Dave

yeah i used to time by ear also..  just that I usually got it too high..

i use direct manifold vacuum..  and if im feeling espeically anal retentive that day ill unhook and plug all other vacuum accessories.

i always remove vac advance line and plug it.  then turn timing to peak vacuum..  it will turn quite bit without change at the peak..  i turn it back down until it drops again.. then back up just enough to hit peak again..

this works very well for me.

if you do this and find that you get a little detonation under load..  (i did this evening) then replace your distributor advance springs.  i did this.. no more detonation..  i dont think the springs had ever been replaced in my truck..  they were very weak. unless youve replaced them recently i would try this before turning timing down a little.

the higher the manifold vacuum.. the "hungrier" the engine is..

Ben, What did you use on the botl threads? I have used Permatex #2 in the past but the last time I put the intake on I used the paste that ARP recommends and most of them are leaking now. I plan to go back to Permatex.

Ben, What did you use on the botl threads? I have used Permatex #2 in the past but the last time I put the intake on I used the paste that ARP recommends and most of them are leaking now. I plan to go back to Permatex.

[/QUOTE]

do you mean the pipe threaded plugs for unused manifold ports ? i used high temp plumbers thread tape