Farmall m

[John 37A]

What kind of power can be expected with a stock stroke 4-3/8 bore farmall m? High compression pistons and a 450 gas head. Under 2000 rpm.

Thanks
 

[EP]

Around 60-65.I have that bore and 1/2 inch more stroke and have 74 HP
 

[CLIFF S]

My SMTA is the O/S Kit same as a 450 and 4 1/8 Bore and Stock Stroke Without any Modifications running threw a Stock Oil filled air cleaner and it makes 60 to 62 HP at 540 on the pto Depending on the weather!

Guessing you Could Be 70 to 75 HP Range!

Cliff S
 

[north puller]

How high is high compression? I would guess 75
hp if compression is 11 or better.
 

[LarryM]

I have a C-281 engine that was stuck when I bought it that I have 67 hp at 540 coming out of it. It has the comformatic pistons so nothing special there at 8:1 compression ande it blows blue smoke. I have figured out that polishing and port matching and the right carb set up make a huge difference. I plan to put a cam in it and see what I can make with it. After that I will probably put a new LP head on it and see what it will do. I just did a 44 Massey with M&W pistons and the horsepower a reground cam from Goldsburg gave it was very impressive. I am convinced that if you use a stock cam you are missing some of the most inexpensive horsepower available.
 

[LarryM]

One other thing is that even at 8:1 compression my C-281 engine will make more horespower on the dyno with a good 93 octane than lower grade fuel. Maybe its the engine or maybe it is the fuel available in our area. Don't know. The all knowing dyno does not lie! All hail the dyno! Just having fun.
 

[John 37A]

I am at 65 hp now with a 4" bore, firecraters, cam from ray at extreme and a smoothed 450 gas head. I am just trying to figure if it is worth my money to get pistons made for this spare 450 block that I acquired. I can't really justify spending the money on a crank and rods (or even just a crank) unless I could find everything used. I would just like to be able to pull 2nd gear in the 5500.
 

[mattwillson]

My M with a 248turbo makes 98 hp @ 540 pto.
 

[LarryM]

4.375" bore stock stroke is 315 cid. Just a quick thought but if you look at the hp to cid ratio and make HUGE assumption that if it were the same then your horsepower would be 82. I have no idea if that is an accurate assumption becasue your flow efficiency changes and your compression ratio changes. Just a thought. What is your carb set up?
 

[John 37A]

Carb is currently a drilled main and nozzles, according to chads' instructions with a 27(?) Venturi. Would need to go larger on the Venturi if I upgrade.

Compression right now is not the highest, a stockish gas head and firecraters with a felpro gasket. I think it is in the 150 psi range, and don't know what the static is.