72 chevy 350 running rough under load!

[martyminnesma]

Originally Posted by geezer#99

A waste to try to explain your timing if you're off trying to find a reason to kill your eddy carb.
Gm engineers don't live at 3500 feet and drive in real world conditions so don't beleive the crap they put out. THey drive and tune absolutely stock motors and tune accordingly. Usually no initial timing plus lots of added vac advance to meet emissions. Wonder what his story would be if he didn't have ported vac available. Cause if he was from the sixties he didn't. Every motor/tranny combo is different. Manifold vacuum for the dizzy is a tuning tool.
Best way to find out whether your carb is running on the power circuit is screw in a mixture screw all the way and see when the motor starts to quit. Try that on your new holley.
Simple cure for hard starts is a power interupter switch to your dizzy (if needed).
My timing curve when I lived in west central Alberta was 22 degrees initial, 12 degrees in the dizzy and 12 in the vac pot. 46 total. 34 all in by 3200 rpm.
No power switch. Fired immediately hot or cold.
350, 11 to 1, holley 3310 750 cfm, edelbrock performer rpm, trick flow heads, 300* duration, .520 lift cam and headers. Dizzy was stock points with pertronix conversion.
I'm not always right, never said I was. Been tuning on motors of all kinds for 50 years so think I've learned a few things.

your timing is basically what i think i need. although 22 initial sounds super high, i wouldnt put it out of the question.

your mixture screw process is how i always tuned the idle. just gave it a try on the holly as well.