Ok all. There's a '79 Fairmont with a I6 in it in the local U-Pull-It. What carb would it have used? I think it's a 200. Here's the story. - Fiance has a '74 Mav, I6 250 1bbl (carter RBS), that's getting about 10mpg. It's eating gas like there is NO tomorrow. I'm pissed at the points, and am converting it over to HEI (tired of resetting points!) this week. The carb on the '74 Mav is a rebuilt Carter with a 'Rebuilt by Holley' sticker. I'm 99% sure it's running super-freaking-rich as if I cause a vacuum leak on the vacuum tree, the idle comes way up (too much gas, not enough air). Questions - Is there some way to jet this thing down a couple sizes? What's teh stock size on it? Will the '79 Fairmont's carb work on it, any better after being rebuilt? I want maximum mileage out of this 250. My 354 Pontiac '77 Firebird gets 18-20mpg with a 4bbl Qjet. There is no reason this Mav can't match it.
79 Fairmont They used a Holley one barrel, some even had a Holley two barrel. Probabky work, linkage adapters will be your biggest problem. Can't be that much but probably also needs rebuilt
My 250 has a Holley rebuild of the Carter YFA that came on the '76s. I used less than 3/4 tank from Pittsburgh to Carlisle, almost 300 miles and I wasn't letting grass grow under my tires. If you're only getting 10mpg, there has to be something wrong. What do the plugs look like? If the points are good and set to dwell ok and the timing is right, the carb has either to be set badly rich or needs overhaul again. The electronic conversion is a good option, but I'd be suspicious that the carb is at the heart of your dilemna.
I agree with Wes. Dad's '73 maverick gets 18-22 MPG on a bad day, and we all know he ain't easy on it! There must be something going on with it. BTW if any of you are interested in the '73 Four door Maverick w/250, lemme know. It'll go for around $1800.
