Is there much hope for turning a 400m into a fire breather? I see the heads as the main obsticle and am not aware of any performance replacements out on the market.

If I decide to to go to a 460 I would like some feedback on what has worked and what to stay away from.

The truck is a '79 F150 4X4.

Thanks, Tony

 

Though not aftermarket, rather than go through the trouble of swithching mills, have you thought of using Cleveland heads on that 400? I have a 79 F150 with the 351M, and ran into the same stopping block for more performance. I searched a few junkyards and found a set of 351C 4v heads, which will bolt right on. You can even use the 400 intake with no rework, or opt for a 351c intake and spacers.

 

Everyone thinks the 400 is useless. On the contrary They make a little power.Check back
Saturday night and I'll repost in more detail
Got to go to work now
Later......

 

On page 3 of this board is a thread titled "is the 351M weak" and contains a lot of thoughts on the "M" engines.

For about $2,000 you could rebuild your 400M, using its 2-bbl Cleveland heads, and easily make over 400 horsepower. Buying, rubiliding and installing a 460 will cost you much more than this.

The reason for the poor reputation of the "M" engines is that they were designed during the gas crisis of the '70s so Ford only made 2-bbl "M" engines with wimpy camshafts. Put a 4-bbl induction system, headers and a good cam in your 400M and you will be very happy. Remember, the "M" engines are just bigger brothers of the 351 Cleveland and you begin to see the possibilities.

If you lay a 2-bbl "M" head next to a 302/351W head you are amazed at the size of the intake and exhause ports of the "M" head and the size of the valves. These heads are fantastic for street-driven cars and trucks so don't sell them short.

Years ago, before aftermarket alloy heads became available, performance enthusiasts would take a set of 2-bbl "M" heads and modify them to fit on their 302/351W engines. This would be cheaper and easier than porting and polishing their "W" heads and would often yield more power.

I have a book on Ford engines by Pat Ganahl, copyrighted 1979 and still available at speed shops. In it he says that you can gain 35 horsepower from a 400M by just adding a 4-bbl intake and carb. The potential is obviously there.

Good Luck.

Bruce

 

The heads on a 400 breath essentially cleveland 2's which are similar to boss 302's. nice ports good flow velocities and livable compression.Look at the valves they rival the 460's(1.65 vs 1.65 2.04 vs 2.07) for truck pulling. Use stainless valves(by SI) due to heat build up and a three angle job too.Blend the bowls a little and match the ports. Pistons are avail Trw #'s L2414 forgings @.030-8.5 compression Check rod to piston skirt clearance though.Crane cam # 52303-1 dual pattern--.461/.493 & 192/204 @.050. you get new springs too. Intake = Edelbrock Performer/ EGR valve for the Emmisions testings. How much power?? Try an easy 350 horse at least in a F-250 this rivals the 460 and less fuel to boot. Death Warmed Over!

 

THERE IS NO SUBSTITUTE FOR CUBIC INCHES!! I garontee my 460 will whup yo 400's ***!!

 

Bring it on to North Carolina (where all the race shops are) and we'll show you a real engine. I guarantee my 400M will dust your non blower 460.

If you have a blower, more power to ya.

 

Look at the technical article on this site for more info. I have a 78 F-150 with a 400M, Edelbrock 600 cfm carb, and non EGR performer. Also headers. Not sure of cam, as engine was rebuilt by PO (I bought it built and fine tuned it). It has 0-60 times of around 8 sec with 35 inch tires and 3.50 gears. It has so much torque off the line it is hard to hook up, and the clutch is fried, so there is more speed in there. It can easily spin the tires in all but 4th gear. It gets aout 13 mpg on the highway, and towing 6000 lbs, it got 10 mpg, while cruising up and down hills effortlessly in 4th gear.

As far as the heads go, if you take the valve cover off, you will see a perfectly arranged set of valves, which I think can be enlarged (but don't need it unless you are revving over 6k), they are the same heads as the 351 2v Cleveland engines.

My engine idles fine at 500 rpm, and is making good power at 5000 rpm.

Just this weekend it dusted one of the new V-8 Toyota Tundras (but just barely)