The Stovebolt Site Forums The Shop Area Engine Shop 216 tuning advice needed

I have a 1950 216 that I am tuning. I've timed it with a slight advance to where it sounds smooth. New plugs, wires, cap, Petronix ignition and have a newly rebuilt Rochester carb. Looking at the attached videos, what sort of feedback can you guys give me? What would you do from here?

Here's the running video:

Here's the vacuum gauge reading

Many thanks for your expertise and advice! I'm pretty new, but have certainly enjoyed learning!

Is the Pertronix a capacitive discharge ignition? If so the secondary-voltage rise-time is much faster than with a transistor fired coil setup; in which case you will need less advance at higher RPM because it will fire the plug sooner in real time which means more degrees advance the faster the engine turns. So I'd be conservative with the initial advance even if it seems to idle better if you have a CD system. I run a MSD, which is a CD system and I use the factory static setting according to the flywheel, then dial in 5 deg with the octane selector. Slight bog off idle but otherwise has run fine these twenty years.

As far as vacuum at idle, I'm at 2500 ft elevation and have a hotter cam than stock so my vacuum readings will be lower than yours but I have about 14-15" at 700 RPM. Pops right up when it goes above idle. By 1200 it's about 19-20" hg. If throttle response is good and it doesn't ping in hot weather when you lug it, I'd say you're good to go.

There are two kinds of Pertronix systems- - - -the ones that have failed catastrophically, and the ones that will soon. Carry a spare point type distributor to get yourself home when the Pertronix takes a dump in the middle of nowhere!
Jerry

Thank you very much! Appreciate your advice!

Try adjusting the idle mixture the way I learned to about 60 years ago- - - -turn the mixture adjusting screw clockwise (lean) until you see a drop in manifold vacuum, then back it out until the vacuum maxes out. Some people claim that the acceleration just off idle improves if the mixture screw is set about 1/8 turn richer after the max vacuum is achieved. Unless you have a leaky intake valve, that should stabilize the vacuum and eliminate the slight pulsation of the gauge in your video. I've seen Pertronix triggers that can be moved on the distributor cam a little, which results in inconsistent ignition timing between cylinders. A drop of RTV gasket sealer between the cam and the trigger wheel might help avoid the error.
Jerry

Thanks, Jerry!