Anywhere between 10 and 12...but that isn't near stock (3.80:1 rear, 245/50-16, 11.2:1 comp, 650DP, custom cam, etc.).
Stock, I would average 18mpg easily with the 302-2v and 3sp with the 3.25:1 rear. With the 3.00:1 rear is was a little better with 25 mpg on the highway.
I have found with my 65 289 with 280 gears, that if I cruise on the freeway at or below 70 MPH, I get over 20. But, if I cruise at a consistent 80 MPH, I get about 17. My car just seems to cruise better at 80 than 70 though, so I sacrifice the 3 or 4 MPG. If you have a 4V, you will actually get better MPG on the highway than with a 2V. Just don't kick in the secondaries.
Team MF Member #200 Posts: 467
Joined: 6/23/2006 Status: offline
im getting like 8-10mpg with my 200ci I6 3.20 gears 5.0 t-5 high performance cam oversized valves roller rockers and i cant keep my foot off the floor but the major thing keeping the mpg so low is i still have my 1brl but stock i was getting like 25-30 highway i should get like 20mpg when i put my holley 2brl on it hopefully this afternoon
Based on an article written by an auto review magazine in the late 60's, the 351w in a '67 Mustang averaged 17 mpg or so. The 351w in a '67 Cougar averaged 21 mpg or so (it has cruise control). This was in a pony car shootout that also included cars such as the Camaro, Firebird, Barracuda, etc. All had similar displacement engines and all were right around 17, except for the Cougar, for their test loop. They were also all automatics.
I don't recall the name of the magazine...I was just bored in a Library one day.
i've done it twice and with a 289 2v with edelbrock intake and carb and full exhuast with a LSD dff and 3.00 gears it said i was gettin 10-11 but i think my odometer is severly screwed up