Replacing the rear main, what else to check?

[trouser chili]

I've just finished pulling the 401 from my newly purchaced 1974 IH 100 pickup, and I've ordered some gaskets and seals to replace the seaping and leaking ones in my motor, but I'm wondering what else I should do before putting the engine back together and in the truck. I've read that in some cases, rear main seals don't last very long before they start leaking again, and it can be related to the crank walking. Is there a way to check the crank thrust? Because I'd really hate to get this buttoned back up and in the truck to have the seal start leaking again next week. To replace the rear main in my case is an engine pull, because the pan cannot be dropped with the engine in-vehicle.

Anything else I should be doing while the engine is out. Right now I'm going to degrease the block, slap new gaskets on the valve covers, intake manifold, oil pan and of course the rear main. I also plan to plastiguage the rear main, as I understand it's the first to suffer from low oil pressure. I have no idea what pressure this engine has right now, as the oil pressure sending unit was missing and the guage non-functional when I removed the motor. The inside of the pan looked good though, little build-up and no bearing material.

[runnamuck]

pry bar and dail indicator to check thust. par it all the way one way. setup indicator, pry it the other way and bam, you got your thrust.

while its out, new thermo/gasket and coolant pump. i would probably check the oil pump clearance and timing cover wear, maybe slap in a chain depending on mileage.