Trying to evaluate my old Ford 601.

Hi, some of you may remember a little bit ago I had questions on here about my tractor not charging. I finally got that issue all resolved. Re-conditioned the generator, new wiring harness, and new voltage regulator. Now for the next issue, it seems its started using more oil than it used to and it is constantly pumping white smoke out of the oil fill pipe. It seems something around half quart in about two hours of full throttle running. oil pressure is between 30-40 when opened up and heated up. it drops as the oil level goes down. I'm pretty sure it needs new plugs and wires. Have not taken the plugs out but they look bad on the outside, wires are lightly cracking and will shock you a little if you try and handle while running. Could the plugs and wires be causing oil consumption, smoking, and loss of power? I really can't tell anything about the points, and distributer, I dont know anything about those parts. It sounds like it runs pretty smooth when first started and doesn't sound as smooth after working a little while. It gets plenty of fuel, has new carborator, fuel sedimate bowl cleaned, new thermostat and radiator, new wiring, flushed and cleaned air filter canister. It seems a good engine tune up is the last thing to restore good power and how it runs. Is there anyway to evaluate the condition of the engine before doing a good tune up? I'm thinking about taking it to the local tractor place and getting a price for new plugs and wires, and have them inspect the points and coil and make sure its well tuned BUT, I don't want to spend the money on that just to find that it needs and engine rebuild, because I can't do that myself, and by the condition of the rest of the tractor cant justify spending that much on this tractor.
As far as needing more power goes, Im trying to pull a like new 5' bush hog. Set at a cutting height leaving grass 9-10" tall. cutter set 3/4 lower in the front than the back. The grass is mostly smooth grass and weeds, very little trees and brush to cut. And even though the grass is pretty thick and long, shouldn't a 9" cutting height be easy enough for this tractor?

Sounds like blow-by past the piston rings if the crank vent is exhausting like you describe. That is high oil consumption, is it a leak or do you have blue smoke in the exhaust.

The oil pressure if when hot and running awhile is not bad.

You should do a compression check on the motor, and see what you have for each cylinder.

Did it sit a long time before, stuck piston rings maybe ? Stuck valve, but it would not run right if so.

Ignition parts would not cause these kinds of engine problems, but it sounds like the wires arecertainly done. I would imagine YT, (this site) has decent quality ignition parts, just avoid the el cheapo junk. Napa can provide good reliable ignition parts, but at this point you had best "evaluate" fully see whats what, tune up parts won't be expensive, but it all adds up.

Its possible you may need a ring job and work done on the head, but I've never liked doing 1/2 a motor, not sure about the 134 or the 172 4 cylinder, what it will tolerate on the bottom end if you do rings and the head.

On the mower, a 5' rotary cutter is a good match for this tractor, and at that height it should cut decent, but thick grasses may bog you down at times, cut higher and take less of a cut as you make your passes around, sounds like you have it level side to side, tilted forward I like it at least an inch lower in the front, new so its got sharp blades, all of that counts when it comes to efficiency. I ran a 5' ford rotary for years behind a '64 4000, (172 4 cyl.) and could go through thick vegetation with it, 6' model would bog down more.

You had best do some repairs before trying to run this one on a rotary mower, that is one of the harder tasks you'll ask of a tractor like this. Don't run that differential dry for any reason.

like Billy said, do a compression check so you have more info.
depending on the results, a leakdown test too.

While blowby out the breather and oil consumption is common on an engine getting tired....
a sudden change from minimal...to a lot...can mean something broke/failed.
Do the tests so ya don't have to guess.
Hey! a t-shirt...."Don't guess...do the tests"

your mowing...
trees and brush are easy.....dense grass is very tough...big load on any machine.
My neighbor has a field that has been planted with some kind of dense grass for pheasants...and wild morning glory and poison ivy is mixed in. His 640 at full throttle and low gear can just barely brush-hog it...at less than knee high growth.

I have a 671 selectospeed that I just picked up with a 5 ft bushhog on it. The previous owner of the 671 redid all of the vitals and the
tractor runs great. That being said, the acreage that I just bought was grown up with a pretty heavy patch of burdock in one spot and the
rest was mostly nice fully seeded brome. I let the neighbor that has horses bale the easy to get to areas, but tackled the burdock and
harder to mow parts with my tractor. In the thickest area I was running full throttle in 2nd on my selectospeed which is only a couple miles
per hour as I could hear the tractor working pretty hard trying to go through it in third.

may look into getting something to do the compression test, maybe find out more about what shape the engine is in. what do I need to know when buying this tester? any of them work? Think I'll go ahead and change plugs and wires, that should be easy and cheap enough, and should at least start easier if nothing else.
I always run full throttle first gear when bush hogging...

Running full throttle is working the engine a bit... You should run it at pto rpm, not full throttle. Also running a hd diesel oil may help lower oil consumption along with running around 3/4 throttle for correct pto rpm if you dont have a tach. If your load is so high that your running at full throttle, you either have too big of a shredder, or cutting too low in thick high crop, or have low power on the engine due to worn rings and or valve and valve guides. Checking tuneup for correct timing, and clean carb will ensure your getting full power with less throttle. However I suspect as the others do you may have low compression and or other problems. pull plug wires one at a time at idle to check for weak cyl.. yes you might get shocked...but pull them from the dist cap with insulated pliers. each one should make the engine lug down about the same,, if you pull one and it make no difference, you found your dead or weak cyl.