The 351m400 have great potential, especially the 400, it was unfortunate for Ford that the first generation pollution controls where introduced at the same time. Dished pistons, two barrel carby, retarded cam timing, air pumps etc etc all combined to give the 351M400 the bad reputation as a smog boat anchor. All the usual improvements like pistons, carby,inlet manifold,good cam turns them into real good performers.The 400 has a 4.0" x 4.0" bore and stroke, now just top it off with a pair of Aussie cleveland head and go big block scrubs hunting.

Google 351m400 for a lot more information 

Pete, one of the Aussie mob. Beechworth, Victoria60 F100 Panel Van, Y-block. 65 Galaxie Country Sedan 390

If anyone knows of a site similar to this one for the 351M and/or 1979 era Ford Trucks let me know.  This site has been so valuable for my 57 ford; I can only hope that I can get the same quality information for my Bronco. Thanks! 

 - John 

John: Lake Forest, IL



'57 Fairlane 500 - Looking better every day.

If only you could see Alaska. It's common practice when you have an extra building to put it on skids and take it to whoever wants to buy it. In fact, the orthodox church is well and truly on wheels!

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People should not be afraid of their government, a government should be afraid of the people.

--Alan Moore

Bonafide Ford torque monster was the 70 Lincoln MkIII 460. 365 Horsepower and 500 Ftlbs of torque off the showroom floor. It could turn your house into a travel trailer if you could get a chain around it. Had a friend who pumped one up and stuffed it in a 78 Bronco. That was a scary ride. Driving one night in the rain down 101 at high speed the roll pin on the distributor gear sheared and the thing backfired so loud I thought whole truck had exploded.



Mark

57 Black Tbird 312/auto

The 351 and 400m engines are torque monsters with some bolt ons.Gas milage always sucks on these,but all in all they are good.I raced a 400m in pure stock oval track racing,used to beat so called 400 horse scrubs with it.FUN,FUN,FUN!

55 fairlane gasser 312 /c4, 57 f100 292/c4, 52 mainline gasser 302/t10 4speed

I would think that the 351m, with it's longer stroke and bigger bore will produce better torque. Does anyone have numbers? I can't find anything on the internet.

My Y is in the 8-10 area in the city and 13 on the highway, in 4th. My mileage really didn't change much with a stock motor compared to the modified motor in it now. It is probably an equivalent gas hog to the 351m Bronco. It has a lot to do with the total package, gearing, vehicle weight, drive line efficiency, aerodynamics on the highway and to a smaller degree on city roads, and the engine. On a big Bronco, many of these things are working against it.


Lawrenceville, GA

I would think another reason the Y would have good efficiency would be that it makes a lot of low end torque, so you don't rev up as much as a 351M.



Take it from a man who has spent a lot of time in his friend's Bronco: Do not make it your daily driver. The wiring is poor, the front ends always fail and take out four wheel drive, and they drink a bunch of gas. They're cool vehicles, but they just can't seem to go the distance every day.

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People should not be afraid of their government, a government should be afraid of the people.

--Alan Moore

I would say that it's just as overlooked as the Y. After all, a version of the 400m has cleaned up at the engine masters. Something about 850hp on 91 octane and repeatedly winning the competition makes me hesitant to say that it's not a great motor. I'm sure it will respond to the same tricks that any engine will in order to improve mileage, tuning, increasing compression, balancing, better carb and intake, etc. But, if you can't control your foot, the same improvements can lead to worse mileage! Some Y-blocks, in there original vehicles and configuration are "gas hogs."


Lawrenceville, GA

thanks guys!  I know the engine was rebuilt about 7 years ago: got a powermax hydraulic cam and "australian heads" among other things.  We'll see how she runs after a little tune.

So basically what you're telling me is that it was not a great motor series and long term a Y swap would be the best  

John: Lake Forest, IL



'57 Fairlane 500 - Looking better every day.

I bought a 1978 Bronco new with the 351 and C-6. Best mileage was 14-16 highway. Drove it for 20 years! Best thing I ever did for it was have heads rebuilt and put in Comp RV cam.

I always remember that truck. Bought it the same week all the stations rationed gas because of the "shortage". That was when gas prices started their climb.

Ol'ford nutCentral Iowa

56 Vic w/292 & 4 spd.