Thread: Thoughts on jetting.

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I think I need to check my power valve.

I like Matt167's advice.

Along those same lines I've found that plugs don't color up well with today's gasoline.

A magnifying glass, some bright light and looking down inside near the bottom of the center electrode's ceramic well - for want of several better words - you'll see the color starting there most times.

I've found too that if the car runs ok you can run a little leaner than you thought since it takes a while to burn a hole in the piston or seize it.

Far as jetting goes, take a look at the Edelbrock carb tuning site and see what percentage change they recommend for your altitude and where you want to go.
The info works great for Edelbrocks and Carters and can be made to work on Holley's and their clones by utilizing a little math.

Add the area of all the Holley jets.
IE: .100 jet's on all four corners gives you .400 total.

If the Edelbrock tuning recommendations say to go 5% lean, fgure what jets you need to lean the Holley down 5%.
IE: 95 jets on all corners.

Seems to work ok on a couple Holley's I've tried it on and it really works great on the Edelbrock/Carters.

Especially since moving to 3300' altitude from 350' altitude.

The roadster still runs good down at the river at 450' altitude.

I'm at 15' above mean sea level.