Farmall h motorbuild

[mcrow4117]

I posted this in the external_link also but wanted to get as much advice as possible I have a 51 farmall H that i have got to do a motor rebuild on and was thinking about buiding it so i can pull farm stock with it and be somewhat competitive. Was thinking about changing to a 300 or 350 head, lp manifold and a carb from a 300 or 350 also what size pistons should i go to to make it somewhat competitive thanks in advance for the info

 

[the tractor vet]

Well we BUILT a H up once for a guy and yes it took some machine work and some MATH and the progressive engine parts BOOK to make this all come together BUT this was strictly a Pulling engine We used 806 Gas pistons .060 over , went with bigger valves , cam work hand built carb off a M , some head work , tricked out the governor a recurve on the dist. did a ton of weight reduction on the chassis and in the light classes it did vary well . But that was all it was good for when done .

 

[used red MN]

It appears by ..External site.. you meant the ..Tractor Pulling.. topic section. I am not sure what you did to post
this but for some reason your post does not show in Modern but the reply by the Vet does, maybe the moderators are still working on issues
after the server switch a couple weeks ago. Anyway, if cubic inches are not limited in your class the most
economical way to get more go out of your H is to find a 350 engine to put in it. Bolts right in, may be some
minor tweeking to the front side engine mount holes due to size changes.

 

[David G]

I am no expert on this, but my opinion would put high compression pistons in it and oversize the valves. I missed the valves when I worked on my MH33 EFI, and could have bought a head with larger valves in it versus the money I put into fixing mine.

 

[David G]

44

 

[the tractor vet]

Cu . IN is what your after and BOTTOM end torque . So for that ya need the stroke and the BORE . Going with a 350 engine is and upgrade over and H for sure BUT your not going to get the knock down lets get down and dirty your going to get by making it BIGGER then a 350 and getting the compression up almost to the point ya don't need spark plugs . Ya know when ya got that right when ya can not hold and old style compression test gauge in with your bare hands and it shoves you away on the compression stroke and blows the rubber tip up the tube . and pegs a 300 PSI gauge.

 

[Highwayman]

Hey Vet
Do those 806 pistons work with the stock stroke?
Or did you have to shorten the rods?
Asking for a friend😊

 

[High Octane]

Have to either lengthen the rods or stroke the crank to use those