Gas Mileage is poor

[data89]

As the originator of this post, I want to add that the next tank fill showed a 12.12 mpg. It would seem that is as good as it gets. I'm going to make a third check, next fill up and then quit. Thanks for all the input, I feel better now.

[hpcgmc]

I drove my 67 shortbed all through high school and college- between about 1977 and 1991 (took awhile to get out of college).

I put a 283 with a Qjet 4 barrel out of 66 Chevelle in it in about 1983. I had 31" tires on it for most of this time. Straight freeway at 60 mph (speedo read 50) I would get 16-18 mpg. I've got my old "logbook" somewhere, I'll double check when I find it. I remember calculating that every 5 mph faster I drove, it cost me 1 mpg.

[68Gold/white]

Originally Posted by data89

You know what, I bought that Holley for my 69 Dodge 318. Now that you mention it, I bet it won't fit on the Chevy with the monojet. I don't know much about carb interchange (obviously), but, you think it can't be used?

Not sure if it can or can't be used. I'm sure your carb mounts w/ 2 studs, you'd have to measure both to make sure. You need to make sure the throttle plate on Holley doesn't get hung up on inside of intake. Fuel line needs to hook up, as well as throttle linkage, and air cleaner. Choke type on both?
Try it!