78custom,
I realize the 400’s have several more horsepower and more torque, how are they for fuel economy? Are they about the same as the 351’s? I realize that a smaller engine doesn’t always mean that it uses less gas. My brother-in-law bought a 6 cylinder thinking it would give him greater fuel economy, it uses about the same as my 351M. I guess it’s the ridiculously high cost of fuel these days that makes me curious.
Thanks,
John24255

 

I've been looking at a 90 250 with, I believe, a 351w in it. The owners said 14-16 mpg. I looked at a 90 150 302, and he said only about 10. Heavier truck, bigger engine, better gas mileage. I guess 351 in 150 would be 17/18?? Not bad for a full-size truck, and 14 years old to boot.

 

My 1979 F250 with a 351M and 100k on it, had been sitting in a farmer's field unused for two years when I found it. Added a quart of oil, took the air cleaner off, a few drops of gas down the carb throat, and turned the key on a cold December day. It started on the second turn of the key, and drove the 300 miles back to my shop (on a temporary permit) without a complaint. Then it sat in the snow for another four months and, once again, started on the second turn of the key to be driven into the shop for restoration.

Now that's reliability.

 

Just bought 78' f150 ranger lariat supercab and it has a 351m, 1 owner truck real clean, no rust, motor runs real good. I don't know much about these 351m's I was excited about getting this thing but they don't sound too depndable. My 69' has a 300 and you can't kill that thing.

 

I got a 400 in mine.. it runs ok, burns quite a bit of oil,, has a brand new oil pump and only carries 50psi when cold!. I had to put hoter plugs in to keep it runing.. but ive gave it hell and keeps going. Like today putting it in 1st and just mashing on it for like 20ft in a mud hole.. lol.. But its soon to be gone for a 428, it will probly get better mailage then my 400 does. My dad has a new 400 crate motor in his F-250 and it carries low oil pressure and over heats its a dog too. but dont smoke any YET.

 

I Recent Brought Mine Back To Life After Sitting For A Long Time. (work To Much) I Love It, I'm Learning That There Are Several Things You Can Do To A 351m.
I Believe That I Have A Carb Problems Right Now. Check Out My Tread If You Can Help.

Thanks 79 Bronc

 

I get 18 to 20 miles a gallon with my M, its also got darn near 215,000 miles on it... shes goin in for a major transplant, gettin a healthy 400 with 400 horses and 500 torque.

gas prices don't phase me one bit

 

Me too, 77 f150 ranger, 351m c6 122k miles leaks no oil, oil pressure fine when I run 10w-40 or 30 oil not straight 30W. It some times does not know at what speed to idle at though.

 

i have a 351m with an aluminum intake. 650 holley sittin on top with a little cam and headers....runs strong to be so old! btw its in a 78 f150 4x4!

 

Ive only seen a hand full or good runing 400ms in my life. Mine has 156k on it and it smokes, leaks oil, and its a dog. but it still starts with a bump of the key.

 

i have a used and abused 1978 f-150 with a wore but strong 351m with too many miles, backed by a new c6, 2wd, supercab longbed, ol bubba's got hedmans with a true dual 3" exaust that i built myself, with two xps mello tone mufflers. u should hear em! hes got sand in the engine, yea im wonderin how it got there too, i put a oil pressure gage on him, and when im idlin and in gear, hes got bout 2 or 3 psi oil pressure. strange though, he doesnt burn any oil, doenst smoke, and even though he makes some racket when hes floored. still takes off like a rocket and never complains. he was hit in the left rear, hes a new jersey truck (quite rusty) but the frame doesnt have any rust on it, but i can stick my foot through the floorboard. still solid though, doesnt creak or rattle, much. this poor ol pickup has had a rough life so far, but i take care of him like my own child, and hes never let me down. i think hes a testament to the durablity Ford trucks. they can take a lifetime of crap and keep on tickin.

 

203,984 as of today & still kickin'...never been out of the truck.

Doc

 

I put mine in a 74 f 100. 750 on top , a good mid size cam, headers. It thumps good.

 

i have one in my 3/4, with the 4:10 gears its not lackin for power i have to say but at 30,000 miles i let it get a lil low on oil and i revved her a lil too high and spun bearings so thats something u wanna watch on them.

 

Steven@nd,I'm not cutting down your 302 and maybe it will run circles around a 351,but out pull it? Give me a break- John