400 big cam advice.

It's common for blocks that haven't been repaired properly, or at all, to leak there. Another way to say it: It was an issue that was common, but needs to be fixed

The proper repair is to sleeve the coolant passages in the block. If they are not too bad you can get head gaskets with thicker coolant passage seals

 

The liner counter-bores in the block would crack and the cracks would continue
into some of the head bolt holes and coolant passages. The cracks did not
cause a problem other than leaks. The fix was to drill and tap the head bolt holes
and install threaded inserts as well drill and tap and sleeve the coolant passages
that were near the counter-bore.
At overhaul the counter-bores were cut for oversize lower press fit liners.
Originally the liner flange was an interference fit in the block. The fix was to
bore the block so the liner below the flange was an interference fit.
This repair would dry up all the leaks.

 

Above is likely worse case scenario.

The gaskets might have been aftermarket which aren’t as great as factory gaskets though I have had very little issue with aftermarket gaskets.

I’d say it wouldn’t be long before it would need the top end gone through.

 

That was what I was wanting to know Thanks