mpg chevy straight 6 ? help

you should get 18-19 MPG............

 

By comparison, my first '53 Chevy had a '58 235 with stock internals, two Stromberg BXOV-2s on a McGurk intake, a Corvette exhaust manifold with dual gl***packs and pipes all the way out under the rear bumper, and an old Mallory dual point. With a stock 3 speed and 3.70 rear, it got 15 or 16 on short trips and exactly 20 on a 450 mile round trip in hot weather at 65-70mph. Something's definitely amiss with your car; if I'm going to pay for 7 mpg, it's going to have to be a lot more exciting than a 235!

 

Yep back in the early 60s 54 -235 15-16 around town and 20 or better onthe road ,and this with a lead footed 16-18 year old.

 

I read somewhere:

"A 235 engine will get between 13-16 MPG on the highway. Less if driven around town. More with the rear gear change, maybe 17-19 MPG."

But my owner's manual says:

"At 70 miles per hour your motor uses almost twice as much gasoline, to go one mile, as it does at 20 miles per hour. Economical cruising speeds are 30 to 45 M.P.H."

I find the latter to be more true when I had the 235 and even now with a period correct 216 installed.

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Here is a link to a '54 owners manual:

http://chevy.oldcarmanualproject.com/chevyowner/54omindex.htm

 

Cruising speeds of 30 to 45 mph would be pretty economical...but modern roads aren't like 1950s roads, any time you're going that speed these days, you're in stop and go traffic. And if you're doing steady cruising, you're probably going over 60

So both are right, in their own way

 

Funny you should say that! I was just on the phone with my dad talking to him about this topic and my recent findings. We both agreed that now is the time for the T5 swap, before Billetproof in June.