TO20 engine out what else should i look for/fix while down

ok I drug this thing home a couple weeks ago from a scrap yard and it probably should have stayed there but now the wife and I are on a mission we want this thing to work and work hard for us for a few years. Unknown to me when I bought it, it had dropped a valve in one of the cylinders. i have it pulled apart on the bench waiting on parts and getting what needs to be to the machine shop. what else should I go ahead and fix or rebuild or at least check out while i have it torn down. abt everything on it seems to have been rode hard and put away wet. I guess my main question is what are common problems that i can fix now so i dont have to a few years down the road. one thing i have noticed is there is an excessive amt of oil in what i would call the bellhousing but the rear main didnt seam to be leaking are there trans seals that should be replaced there and how difficult? I really didnt buy this as a restore project but it has turned into that. I just took a little gamble that all it needed to run again was some electrical work and this is were im at. just to say before i hear it a few times over i already know im gonna have more in it than its worth i just would like to breath a some life back into it.

Bad about cracking block between cylinders. Check that area very close. I also have a few parts fergies.

Yes to the other response, there can be cracks in the webs between #1&2,2&3,3&4, the bottoms mean more than cracks at the top. See to these, and change the clutch, and the seals on the transmission, a bigger and more miserable job that the engine to many of us- but no better time than now.
While the radiator is off changing the pivot pin will be very easy now too. Don't worry about you and your wife getting 'a few more years' out of it- think in 'decades' before all this will need to come apart again. Just don't be cheap, get the crank turned, the complete overhaul kit, and take your time, many guys on this forum did this several times, so don't stay stumped, just ask!

I am willing to bet that you won't reach my mark for money spent on a '20. Don't try. All other machines have at least broken even. Her '20 is a money pit in the dirt. I have another money pit that floats...
What else to do? If your Fergie was not mixing oil/water this is a good thing. KN block seal can do wonders once the engine is running. Hope you paid attention to the direction the conn rod oil squirt holes were pointing when you took it apart. Zip tie works great to keep the front crank spacers in order and not getting lost. Fill the oil pump with vaseline to keep from pumping dry, replace the rubber fittings in the oil pick up line by visiting your local hydraulic repair shop.
First fire should get the engine running as fast as possible to keep the lube on the cam/followers and not getting wiped off when first dry cranking the engine. Heavy duty oil, NOT energy conserving should have zinc in it. Zinc keeps the cam happy over the byears by leaving a film behind and reducing dry start in the future. Energy conserving drains away and leaves no film for future protection.

A very good investment would be a shop manual.

Buying something like this will come with a fully amended application of Murphy's Law! LOL

What have you checked in the engine? Considering the age, I would completely disassemble the engine, measure everything, assume nothing. This is where you need a manual. That engine has wet sleeves, which means there is an oring at the bottom of the sleeve. If you're not replacing the piston/sleeve assemblies, the orings need to be replaced while it's apart. If you're having outside machine work done, don't let them assemble anything! Bring everything home and double check their work, or have another shop check the measurements. The rocker arm assembly is a commonly over looked component. Most likely it will be worn, they can be bought as a remanufactured assy.

There is a seal in the transmission input shaft, easy fix with the engine out. The transmission is prone to collect water. It gets in around the shifter boot and condensation. It has probably been sitting and filling with water, raising the oil level until it came out the input shaft seal. There is also a hydraulic pump in the bottom of the transmission. They are known to have valve problems. It can be repaired or bought rebuilt.

There aren't any original new parts available, only aftermarket, commonly from India or China, buyer beware! Good news is you can get just about anything you'll need. This site has a good selection. Ebay and individuals are good sources for used original parts.

Good luck with your project! Keep us informed, lots of help here!

Ok, manual already ordered, pull the hydraulic pump and rebuild i will start on this after i get a manual. the rocker arm assembly already needs replaced it broke a spring and dropped a valve.

yes i marked all rods position and front. crank spacers? the front has a thrust bearing and one thrust washer thats full circle around the crank i have not taken off yet because the gear is still on.

crank is getting sent off(hopefully to a good machine shop we will see). i havnt got the liners out yet im going to make a puller as soon as i get back to work. I didnt see any cracks as i read this before but after i get it all cleaned up it might be easier to see. I'm ordering a kit VERY similar to this one (http://www.yesterdaystractors.com/Ferguson-TO20_Overhaul-Kit-Comprehensive_20K600.html) as soon as i get the crank back from the machine shop. the engine dropped a valve i will have the rods checked also at the machine shop. the valve head went clean through the piston. the crank and rod bearings looked pretty good really. trust me im not scared to ask questions im sure you all will get tired of me asking.

i might hit you up later on as i think this one would probably been better off as parts but like i said im in it now and by the time i get done with it i should be pretty confident.

And lots of interesting old iron.

Many have given you the major components and they are all important. but if you want it to run properly do the governor while it is easy to get at.