Redwood

Not mine but somebody might be interested. https://seattle.craigslist.org/sno/hvo/d/snohomish-td-crawler-parts-international/7375805414.html

TD9 -91 series and UD350 both use a 4.5 inch diameter piston but these are diesel engines. Not sure what else is out there.

Definitely a TD-9 or 9A as the air cleaner is between your legs. the later models (91 and 92 series ) moved the air cleaner under the hood so your crawler could easily be from 1940.

You may be right they started over in 1959 with the introduction of the 92 series, which utilized the 6 Cyl direct start engine.

This would be a 1940's model According to the serial number listing at the top of the page.

Yep, that works, but not nearly as much fun.

Not really at the Gucci level as I found the torque system on Craig's List for $125.00. Cost more to make the socket.

This is what I used to torque the final drives on my TD14 (720 ft lbs). Had to fabricate the custom socket. The torque system was designed to torque down helicopter rotor hubs, good for 1200 ft lbs. 100:1 gearing.

https://goldcountry.craigslist.org/hvo/d/martell-tracks/7336349783.html Not mine but may be worth it if it checks out

If it was me and I did not plan on using the dozer much I would just swap the better head onto the 335 motor. I do not believe that there was a huge performance difference between the two engines. The TD-9 engine and sleeves are also getting very expensive. Last time I checked they were selling for $500.00 per hole. Another option would be to get your 4-3/8 inch sleeves bored out to 4-1/2 inches and clean up your old pistons. Rings for either engine are still readily available through Hastings, but not cheap.

Crankshafts should be the same they just changed bores over time 335, 350 and 370 cubic inches, 4-3/8, 4-1/2 and 4-5/8 inch bores respectively. You will have to make sure you get the correct head gasket for whichever engine you are using. if I remember correctly some of the early engines had the sleeves flush with the deck and the later engines they protruded several thousands. So on the early engines the gasket set on top of the sleeve and the later engines they went around the sleeve flange. Good luck.

Trucker is correct. These holes are also used when mounting a winch. See photo below. Gene

I would replace the fuel filters first before digging into the injectors or pump.

There should be no difference between the two injection pumps or engines that I know of.

yes, a little confusing when you first look at it