Hey Rick,
I'm not familiar with the Cleveland blocks, but I know you could do it pretty easily on a Windsor motor. So if it's the same, you're in luck. You should be able to just drop the pan...on a Windsor, I think there are about 24 bolts. Some are in the front cover, while the majority are in the block itself. You should be able to get the
oil pan off without messing with the tranny. In the worst case, you would just have to take off the inspection plate on the bellhousing if it has one. But you probably won't even have to do that much.
Depending on how long the motor has been together, I wouldn't worry about changing the rear main seal. It should be fine on a not-too-old rebuild. Just use your own discretion on the
oil pan gasket. Depending on what they used to put it on with, it may be hopeless to get it off without tearing it up.
While you're in there, you should be able to check the
oil pump. It's probably not necessary, but you should be your own judge. I don't know if you'll have to pull the distributor or not. Like I said, I've never worked on a Cleveland motor, so I'm not an expert here. Maybe some of the other gearheads can help out. When you take the oil pump and pickup out, the oil pump drive will most likely want to come with it. On a Windsor motor, there is a little flange that keeps the oil drive from coming up towards the carb when you pull the distributor, but nothing keeps it from falling out the bottom when you pull the pump out. So I assume a Cleveland is the same. So be prepared to fool with all that crap too. If you pull the distributor, make sure and mark where the rotor was pointing so you can get the timing back to where it was initially.
If you have a main girdle, forget about checking one main bearing. You'd have to take the girdle off to even check one of them. I guess it wouldn't hurt to take a cap off to check the bearing. You can pull it off, and then clean it with lacquer thinner to really see any wear marks. Make sure it's torqued back to the correct torque when you replace it.
Hope this helps you some. I'm sure the other more experienced members can add to my suggestions.
Take care,
Brent