Been using Edelbrock 4bbl carbs for a while, always seemed to work well but ran rich. When I put the last car together (63 Daytona 259) I had a bung welded in the exhaust for an O2 sensor so I could plug in the Innovate LM-1 air/fuel analyzer and solve the problem once and for all.
Not surprisingly, the stock 500CFM carb is jetted too rich. I stepped the main down from .086 to .083 and still was running rich at cruise. Dropping down to .080 gives a very slightly rich condition - around 14.0 - 14.5, very acceptable as the ideal is 14.6 according to Edelbrock. Going a little richer gives better performance, a little leaner better economy.
Acceleration was still rich, I wound up with a 1463 (067 x 055) metering rod and a lighter step-up spring (yellow, set for 4" vacuum. stock is orange, 5" vacuum)
I'll drive it for a while and see how I like it and what the plugs look like after a few hundred miles, but it seems to get off the line much better.
Might play with a 1406 later and see if there is any difference.
Not surprisingly, the stock 500CFM carb is jetted too rich. I stepped the main down from .086 to .083 and still was running rich at cruise. Dropping down to .080 gives a very slightly rich condition - around 14.0 - 14.5, very acceptable as the ideal is 14.6 according to Edelbrock. Going a little richer gives better performance, a little leaner better economy.
Acceleration was still rich, I wound up with a 1463 (067 x 055) metering rod and a lighter step-up spring (yellow, set for 4" vacuum. stock is orange, 5" vacuum)
I'll drive it for a while and see how I like it and what the plugs look like after a few hundred miles, but it seems to get off the line much better.
Might play with a 1406 later and see if there is any difference.
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