mid teens around town, high teens on the highway averaging 75mph. this is rare - I can't keep my foot out of it most of the time.
My highway mileage suffers because it's a higher stall converter than it should have for a 2.76 gear. It's in drydock right now for an overdrive and 3.23s.
It's real well behaved and loves to lug. I need to turn down the advance and lean it out to get any idle lope at all.
1rst gear is a silly joke on 275 all seasons. Throttle response is instantaneous. If we mash it at the same time from a highway roll, I can hang with a few local turbo or giant cam/giant port NA cars that are breaking into 11s.
The extremely fast ramps on this cam make it act bigger than it's specs imply. I also credit Dave Hughes' valve job for a lot of flow.