I just bought my ranchero back and forgot how ****py the MPG was, I am gonna replace the too big carb a 600 cfm. Its new.. too bad. What would you run for a carb? Its got a four barrel manifold, but I have a two barrel manifold also. 500 cfm is whats avail, and its still a little taller than stock. I dont burn rubber and drive it rain or shine 30 miles a day. Got any good tips. I already put in a pertronix.
I have a Holley 450 or 390 - forgot which- on my 292. But it isn't on the road yet, so why did I even type this? Your Ranchero is cool.
The type of carb will have very little effect on fuel milage if it is jetted and tuned properly. How you drive the gear ratio have more to do with it. A four barrell wont use any more gas than a two bbl unless you have the four bbls open. 292 and 312s typlically didnt get good fuel economy. About 20 years ago this farmer came by our junkyard. He asks have you got airy a good 272 or 292 ford motor. They never made a good one was my reply but we have a 390 we can sell you. He had us put it in a 1955 f 600 grain truck all the time he was worried that it was gonna be a gas hog. About a month later he came by bragging that hill that he previously had to crawl over in granny low on the low side of the two speed rearend. He went pulled with no strain in second gear on the high side. He also stated gas milage was improver by 1/4 over the original 272 (boat ancor) OldWolf
Thermal efficiency and Low end torque win hands down every time. A Y block has **** house intake ports which reduce that thermal efficiency .A FE has more efficient designed ports and combustion chambers. Which both add up to more more torque so it stands to reason it's going to feel stronger and use less fuel than a small 292 in a 4-6 ton truck.
i run a truck 2 barrel on my 312 y-block with protrixc and3.10 rear still not great gas mileage about 15-17 on highway
If you are running a 1850 Holley 600 Cfm remember the primaries are about 1/3 smaller than the 2bbl so mileage should be better,try going to a 55 power valve and 61 primary jets,run a black spring in the secondary vacuumn,so it opens later.Some of the Y-blocks- forever guys really like the 390CFM 4bbl.
Distributor is stock with pertonix, so is the trans (auto). and I did find out its a 292. I have no idea what the gears are. It shifts into second at 35 and goes down the road nice at 60. The carb is a toilet, its getting like 10 MPG. Does holley make a 450cfm or am i gonna start looking for a stock carb to build?
stick with the four barrel but loose that damn holley- the only thing they're good for is drag racing( i know others disagree). get one of the carter afb's or an edlebrock copy - about 500-600 cfm. lean the primaries out until you get poor performance that you are willing to put up with and then back up a size or two. richen up the secondary to get a good plug reading with wide open throttle. make sure the advance in the distributor is functioning properly. don't be afraid to play with the timing and jetting- remember the factory specs were for a time when fuel quality was a way of life-poor at best.
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