625cfm street demon

Mike 340 said

Hey everyone, I am new to this forum just wanted to know if anyone has tried the street demon 625cfm carb?
I just put one on my 340 and I have found that it seems lean. My engine is a 68 block with 71 J heads and tq intake with 71 340 exhaust manifolds and a comp cam 268xe . Any input or information would be great.
It's just a cruiser 5500 rpm . Already have the calibration kit.

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If it's like the Edelbrock it should have a step up rod chart. I would first find a back country road for doing the tuning. Start out with making a full throttle pass and while coming to a stop shut the motor off. Don't let the engine idle. Now pull a couple of plugs and see how they are burning. If they are looking a little white in color I would say you are a little lean. If that's the case go by the step up rod chart to see which rod you should use. You may get to the point based on the chart where you may have to change jets.

If your plugs look a medium to dark tan then you are in the ball park. If the plugs are black or even wet you are too rich

Of course everything else with the engine should be up to speed.