Is my MPG way off?

[Caprimaniac]

Hello again; good to be back in the Weber crowd.

Nut much traffic in here now, but I'll pu out my Q anyway.

Car is 2400 lbs w/ driver. 347 CUI, 2.02 inlet valves, 306 deg (adv) cam with 0.6" lift.

Running at highways, 45-60 mph. One toe at the throttle, accelerating as little as possible, I get 14,9 MPG.

At last setup, with injection setup, I got 13 MPG.

Should it be higher than 14,9 with the Weber setup?

If I want it lowered with current engine setup, what would be the first steps to try out?

I have thought of two things:

1- Be sure I have a thermostat. If not, the engine will operate at a low temp on the highway- not good. (I don't remember if installed the stat; have to drain to have a look this winter.)

2- Change to a smaller idle jet. As throttle is barely open, marching on in 2000- 2500 rpm, I'd guess it's suckin from idle/ transition holes?

Please correct me if I'm wrong.... I went bigger on idle jets to get rid of a transition- miss. And I did! (Luck or other changes might be the reason. I did build a new linkage like this
Linkage Plate and with a good return- spring, all has been really well after.)
,

I'm tempted to tame the engine with a smaller cam, but IDK if that would make a ton of difference.

Thanks
RS