Efficiency Build...

[Brown_Muscle]

So I want a more fuel efficient engine, a couple more MPG would be nice. I was wondering if GT-40 heads and a smaller (500CFM) 4 barrel carb might help, as well as make some more power. I have a 2.5" headers to tails exhaust (with a 2.25" h-pipe). Has anyone tried this combo on a 351, or know of any other mods I can do? I get around 10MPG city and 18MPG highway. I'm putting in a 3.27 rear to replace my 2.73, so I should get better in city, but in the long term a more efficient engine would be nice.

[turbo2256b]

351Ws realy need even on a mild build for economy smaller versions of aftermarket aluminum heads ported GT40s might do alright. All production ford SB heads were realy designed for 260, 289, 302 351cubes are a bit much for them.

[gadget73]

they'd still have to be better than the stock castings though. 351's in stock form are pretty starved though. AFR165's might do you well.

[johnunit]

I think that's a good start. Also look into aeromods. The ones I have planned so far are the airdam from a 90s Chevy 1500 truck, and something to bridge between the bottom of the trunk and the rear bumper so it doesn't catch air.

Roller cam and rockers should be worth something, but you'll have to drive a lot to make your money back through gas savings. Of course any weight reduction will help.

Don't just slap a carb on, there's a definite science and art to getting a holley carb tuned, and it'll make a big difference in fuel economy.

Also consider a block heater, even for not-so-cold days. I've heard of people being able to avoid significant warm-up times and using the choke in the summer by using a block heater.

[Brown_Muscle]

I feel semi-confident about carb tuning, so that shouldn't be a problem. I was planning on doing what Dave did with the aero under shield for the front, under the engine. I have the police "air dam" or whatever you would call it. I would not be opposed to porting the heads and port matching the intake. Not sure how much of an impact the aluminum driveshaft will have, but i suspect it will help a little with city driving.

Block heater would be nice, I don't know if i would have patience to use it enough though, our old turbo-diesel mercedes has one, and has been used in sub-freezing temps, but i personally never used it.

[Mainemantom]

X2 on the block heater. Both of my winter cars have them. I plug them in when it gets around 20 degrees. It makes a ton of difference. Easier starting and warm heat right away.

[gadget73]

Not really necessary if you aren't driving it in the winter, which you ought not be if you value your quarter panels. Thats what aeros and other disposable vehicles are for

[Brown_Muscle]

So true, salt goes on the roads, car goes in the garage.

It's always 20 degrees in Maine anyway :P

Not really necessary if you aren't driving it in the winter, which you ought not be if you value your quarter panels. Thats what aeros and other disposable vehicles are for

[johnunit]

Not really necessary if you aren't driving it in the winter, which you ought not be if you value your quarter panels. Thats what aeros and other disposable vehicles are for

I've still see it help in cars like a carbed small block where warming the oil/coolant with a little electricity is way, way more efficient than doing it by running the engine. Even on fairly warm days.

[HiFiMerc]

Thats what aeros and other disposable vehicles are for

That's why I bought an Aero for a winter beater.

It has grown on me though, in the almost 3 years of driving it.

[crazyman]

Compression and cam. I got 19mpg avg corrected out of an 82 3/4 ton gmc with 3.73's and 31's in highshcool with a teenage leadfoot. 305 heads on a 350 and a 204/214 cam. Eddy intake, q-jet, iron manifolds. Look for smaller cc heads, keep the port velocity up, and use a mild cam that doesn't thump. As much ignition advance as it'll tolerate without pinging too..

[turbo2256b]

Compression and cam. I got 19mpg avg corrected out of an 82 3/4 ton gmc with 3.73's and 31's in highshcool with a teenage leadfoot. 305 heads on a 350 and a 204/214 cam. Eddy intake, q-jet, iron manifolds. Look for smaller cc heads, keep the port velocity up, and use a mild cam that doesn't thump. As much ignition advance as it'll tolerate without pinging too..

All factory SBF heads are too small for best efficeny from a 351W as the port velosty is already to high and not enough air flow for 350 cubes most efficent cylinder filling.

If you were to compair port size flow of a SBC head to a SBF the closest match would be 351C 2V heads.

My F150 4wd w/3000 stall 400 pocket ported C 2V heads,headers, highway towing cam 230ish at .050 duration hits 13 MPG Highway. 4:11 gears 33" tires. At highway speeds its slippage due to the Stall is 25%, with a tight converter it would be close to 18 to 20 MPG.