1968-1982 Chevrolet Corvette (C3) — MPG & Fuel Facts NO OFFICIAL EPA RATING

The EPA's public fuel-economy dataset only goes back to 1984 — the 1968-1982 Chevrolet Corvette (C3) predates it, so there is no government-rated MPG number for this car anywhere, including here.

Estimated 10–21 MPG combined.

Period road tests of the early big-block cars found the low end: Road & Track's 1969 427/435hp test averaged 10 mpg, and a period review of the 1968 427 reported 11-15 mpg. At the other end, the EPA's directly-verified 1978 Gas Mileage Guide rates the 350 V8 automatic at 15 city/21 highway/17 combined, and a UK Classic & Sports Car buyer's guide states an overall 'Mpg 11-18' for the generation. The wide spread reflects big-block vs. small-block engine and manual vs. automatic across a 15-year run.

This is our estimate, not an EPA rating — built from the period road tests, marque-specialist guides and corroborated owner reports cited below, hedged where sources vary. Treat it as a ballpark for planning, not a spec to rely on.

C3 Corvettes ran 327/350/427 CID engines (1968-74, including the 454 CID big block from 1970), downsizing to 350 CID small-blocks (L48/L82) by 1975 as emissions rules tightened, a California-only 305 CID V8 in 1980, and a Cross-Fire-injected L81 350 in 1982. Road & Track's 1969 test of a 427/435hp car recorded an average of 10 mpg (consistent with its stated ~200-mile range from a 20-gallon tank); a period review of a 1968 427 reported 11-15 mpg (220-300 miles per 20-gallon tank) — both entirely plausible for a high-compression big-block on leaded period fuel.

The EPA's Gas Mileage Guide data, read directly from the government's raw text files, gives the clearest small-block-era figures: model year 1978, 350 CID V8/automatic = 15 city/21 highway/17 combined; manual = 14 city/19 highway/16 combined. Guides for 1979-82 report only a single 'estimated mpg' figure (13-15 depending on year) rather than a city/highway split, which is a real change in the government's own reporting format, not a data inconsistency — flagged here so the site doesn't overstate precision for those years.

Classic & Sports Car's UK buyer's guide states a generation-wide 'Mpg 11-18' for the C3, which brackets tightly with both the period big-block tests and the EPA small-block data. Owner-forum reports (Corvette Registry) independently cluster around 11-16 mpg mixed for stock small-block cars, with outliers only for heavily modified engines (e.g. a modified 1969 427 with an aggressive cam reporting ~6 mpg, not representative of stock configuration).

Sources: EPA Gas Mileage Guide raw data, model year 1978 (fueleconomy.gov) · EPA Gas Mileage Guide raw data, model years 1979-1982 (fueleconomy.gov) · Classic & Sports Car — "Buyer's guide: Chevrolet Corvette C3" · Curbside Classic — Vintage Road & Track Road Test: 1969 Corvette 427/435hp · Curbside Classic — Vintage Review: 1968 Corvette 427 · Corvette Registry forum — "MPG, what do you get?"

All classics Search Chevrolet Corvette (C3) on FuelFacts (in case a later model year is in our 1984+ EPA data)