Inital Tuning of Dual Holleys

[Wreckless Warren]

I achieved a nice 825 RPM idle with 15 deg of initial timing with this method. I also have 15-16 inches of vacuum at idle. I took very small steps and did not have the progressive linkage installed during the tuning. Having the engine on the run stand made constantly removing and installing the carbs easier.

I'm glad to see Barry's comments about having any throttles completely closed. On my last adjustment of the secondaries I had 650 RPM at idle and that was too low. Just an ever so slight turn in evenly on both primaries off of the closed position brought me up to 850 RPM.

I was going to make another adjustment so the primaries would be closed but I will leave it as is for now. Obviously more tuning will be required once the engine is in the car and it's driven.

Since I have 15-16 inches of vacuum at idle and 6.5 power valves, should I change them to 7.5's?

Thanks for every ones input. ww

[My427stang]

See how it runs, and even better, if you can run a line inside with a vacuum gauge while you do it.

If it stumbles a bit at light roll on and cleans up as it passes 6.5, try a 7.5 or even 8.5.  However, likely you are just fine with what you have

[e philpott]

I took very small steps and did not have the progressive linkage installed during the tuning.

Thanks for every ones input. ww

sweet on getting it dialed in !! .... I bought my stuff used and previous carb owner had the linkage modified ( wacked off) to the point where there is no changing anything ( progressive linkage on the secondary ) I wish I could have eliminated the progressive linkage for tuning but couldn't , they also had the primary carb clearenced for the linkage assembly not the secondary so the previous owner had the carbs on backwards thus only allowing less than 3/4 throttle ( no wonder he said it didn't make any power , lol ) ..... I had to de-rig  a few things on it but real happy with how it turned out