Tuning the 390

[burner1]

Since I swapped from Fuel Injection to Carb I have been doing a little tuning. I write this should someone be interested in the notes. All this based on a vacuum and O2 gauge I have mounted in the dash.

I set the vacuum advance to be manifold instead of ported. Far better idle.

Initially running a little lean. Carb came with .051 jets. Moved to .060
.060 too rich worked my way to .056 and still a little rich; although it runs fantastic.

Secondaries were a little lean but the 390 has a metering block not changeable jets. Removed block and openings at bottom were .052. I drilled them to .055. Secondaries right on the money.

There was a hesitation with secondaries kicking in. I swapped the springs in the vacuum secondaries to the lightest spring Holly has. All hesitation is gone. Acceleration is instantaneous in all areas of acceleration.

Took the car on a trip last weekend. Mileage was 28.2. I think I can get a little better with a little more tweaking.

Runs fantastic!

[mgb260]

Great info, Gary!