Chrysler 360 w/ W2 Econo Heads, Headers, 30.over

Crazyguy, that's a good point, and I'll take it into consideration. I'm confused, so the Avenger is what I need or what I don't need? I guess I should go back to putting metering blocks in my HP 4150 and see how she goes?

If you mean adjustable meter block, you better have someone tune it at a shop that knows what they are doing.

you have a 750 and have issues with lower speed drivability yet you consider a bigger carb that comes calibrated leaner than heck?

The cam is your main problem, just so you know, the carb change will bandaid the lower speed issue, which is alright to do to until it costs as much as a cam swap.
Increasing the initial as much as it can handle while maintaining the same total would be of great benefit to you as well in the low speed and milage zone.

My only advice, go 650-700cfm or change the cam cause your combo is not for milage, it's for going fast and writing blank checks to your gas tank.jmo