That motor isn't too bad, at least you can still see the bottom row of head bolts. The intake ports are very oily, which would indicate to me the bottom of the intake gaskets were probably leaking. The oil on the outside is pretty standard big block stuff, especially the ones with the factory hipo exhaust manifolds they cook the cover gaskets. Buy the high temp valve cover gaskets, or you will get real good at changing those gaskets.

I think, were it me, I would see how much slop the timing chain & gears have. Pop the dist cap off, and rotate the motor in one direction for a short distance, then stop, mark the rotor position, and change the direction of rotation and see how many degrees of crank rotation you get before the rotor moves. There should be very little distance, if it seems like a lot, I'd pull it down and change the timing chain and gears. Those 2 bbl big blocks came with a plastic coated cam gear and time is usually not good to them, the miles don't seem to be a problem until the mileage gets near the 100,000 mile mark. Over time, the plastic gets hard and starts to break off and the timing gets sloppy and the plastic tends to plug up the oil pick up screen.

Intake gaskets, timing chain and gears, and the oil pump pickup screen are the things that most concern me about the old big blocks. The valve seals would be somewhere down the list, but those seals are a lot older then they were when I was playing with a big block. Gene