i for years ran a 73 charger with this combo.....
318,wieand action plus,out of the box holley 600,mopar orange box and distributor,36 degrees total timing,manifolds,2 1/4" duals with h-pipe,40 series flows,full length exhaust,833 aluminum overdrive 4-speed,performance clutch,8 3/4" rear with 2.94 gears and sure-grip. 215/70/15's on 15X7 cragars. drove this car 3 times to columbus to the nats,(1000 mile round trip) got 23-25mpg running 75-80 mph. tached 1800 rpm at 75 mph. car pulled hills just fine. was it a powerhouse throttling up at 70mph in overdrive?? no. thats what i had a 4-speed for.if someone is trying to figure out how to keep a sizeable amount of power,while still in a higher gear,and low cruise rpm,i say,stop being lazy and downshift already. i'm not sure what "lugging the engine" at low rpms would be entailing,i mean,fire trucks,cop cars,and wreckers do it all day long sitting still.pulling alot of amps,pumps,etc.just my 2 cents......