gas mileage Mechanical vs Vacuum Secondaries

1wild&crazyguy said
LXguy, what it looks like on paper to you and how it actually runs are 2 different things.
'not talking about the chart above'
I've been running run of the mill holley street DP's for a long time, and compared to the vac secondary carbs, there really isn't a diff noticed at the pump, but the ET's sure are better with the DP's and 'my combo's' which have to be streetable since I drive primarily on the street/hwy's.

Well, "notice" is sort of vague. The mileage on my hot-rod could vary pretty easily by 3-5 mpg before I'd notice. I don't drive them a lot. I hot dog when I've got them out. Unless you were specifically tracking it, a change of 1-3 mpg is going to be imperceptible, and if you were specifically tracking it, you'd drive in a pretty sedate fashion, which would obviously close the gap between the two.

How much ET difference is there? Are you letting off the gas to shift the manual or are you powershifting?

1wild&crazyguy said
I was getting 15mpg with my 10.1 344sb .528 solid w/+5*, running 24*int/32*total 3.73 gear, 4 spd , ported X heads, w/weiand single plane-750 double pumper.

Oh come on. Is your speedo corrected and verified for the different gear and tire you're running? How many tanks did you average? Any highway driving in there?