400 vs 450 head

[johninmn]

Whats the difference between a Farmall 400 and 450 head? Not a lp just straight gas 450.

 

[farmall66]

none but check your casting numbers first.

 

[johninmn]

8574 da

 

[puller1]

I don't have the casting numbers for the Farmall M heads but I think you will find that is one of the versions you have.The 400/450 heads are 3621741R1,362920R1,362292R1 with the first one listed being the best compression.

 

[johninmn]

8574 da is the head I have now which I believe is off a 400

 

[D Slater]

8574 DA head is older than a 400. Its a C 248 engine gasoline head.

 

[james rumph]

The best head for a "M" based motor is a 450 LP.
Then the 450 "GAS" ..

The LP has the smallest combustion chamber, then the 450 gas.

I have always been told this in this order.
I had a 450 gas head done several years ago and that motor preformed great with good numbers on the dyno.

 

[Charles E. McNelly]

Nothing. 362174 is the gas head on both.
Charles