Normally getting 12-13 mpg, gas over $3, got 11.3. All tuneup etc.
up-to-date but poking around noticed the vac line to the distributor
advance had fallen off. Put it back and noticed better power right
away. Would this have caused the drop in gas mileage? This is a
'72 El Camino 350/4 barrel Edelbrock Intake TH350 Auto. Meanwhile
have to get a longer hose, the old one is not tight enough at dist
from heat expansion and barely reaches.

Yep, attaching the hose that works the vacuum advance should help your mileage and drivability.

Thanks, I'll get a new hose this weekend. I put a zip tie to keep the old one tight and it's holding but there's stress on it from being too short. Have to do anything we can to save gas these days.