That's about what Iam getting with my 410's. I little less mpg but a lot more fun.
[Z06] 390 rear
Le Mans Master
Joined: Apr 2001
Posts: 5,941
Likes: 281
From: Was New Orleans but swam to Baton Rouge LA
Cruise-In IX Veteran
Well after I did the head swap on my car with the cam I could get 31-32 on interstate cruising. After the 3.90 rear I would get 28-29 so expect a few mpgs to drop.
Le Mans Master
Joined: Aug 2007
Posts: 6,473
Likes: 297
From: Orange Park FL
Instructor
Joined: Oct 2005
Posts: 224
Likes: 0
From: FL
Once you install the 3.90s and feel how much it wakes up the SOP feel you will be in the throttle a lot more at first. So initially you will realize a big drop in gas milage.
If you drive the same you will lose about 2-3 MPG highway and 1-2 in the City.
If you drive the same you will lose about 2-3 MPG highway and 1-2 in the City.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
CHICAGO CREW !
Joined: Nov 2001
Posts: 17,591
Likes: 93
From: We are living in a Bazzaro World everything is upside down half ass backwards !
CI 4-5-6-7-8-9 Veteran
St. Jude Donor '06-'07-'08 & '12
3:90s 2800 stall converter still getting 28 29 mpg ...........best mod I ever did