If I read the post correctly(a big if). You decided to pull the pan to remove sludge. The center line measurement off the crankshaft will be simple. The timing cover will be simple to remove with the oil pan off. The drilling of the mount can be done after you get the measurements. I would roll the engine to the manifold side after I removed the carb and oil lines. Along with the canister if you have one. The manifold is stronger than the draft tube and the distributor. The valve stem seal can be addressed by pulling the rocker arm shaft. None of this is hard to do. Don't worry yourself into a lot of money yet. These old engines aree happy campers most of the time. Get it started, does it have oil pressure? yes, good. No? shut it down and find out why. Is the compression good in all cylinders? Cool. If not, then worry. It might just take some time to reseat the rings. It might take a few miles to loosen the rings and piston. It might be worn out but that will show with not too much spent yet. With the timing cover off I think the bolts can be placed for the mount.
