I have a few questions. What kind of gas mileage do people actually get in these the RS and Z28 I see what the ratings are but I know that is not real world. How much of a difference does manual vs. auto make. This will be a slow project car for me if I can find one.

 

My old 91 RS with an automatic got 27 mpg on the highway. I never bothered checking in town driving.

 

My 87 IROC-Z averaged around 20 mpg when it had the stock 5.0L engine.

Now it's more like, 15 :V Though it was running pretty rich, so it should improve once I finish working on it and get it tuned properly.

 

My old 1994 Z28 auto would average 24 MPG on the highway running 70 to 75 MPH. Not too good in city traffic, 15 MPG at best.