You have to see the engine to know what it is. It could be a 413 or a 440, it could have the weird heads or heads that look like passenger car heads. It could be a drop-in after you switch oil pans and pickups.
Blocks and cranks will be the same, you may have to swap on the passenger car heads, manifolds and water pump stuff if it has the weird heads.

Do not believe those who would have you worrying about cooling, the basic cooling system is the same for all. Some may have extra holes here or there but, if you use a passenger car head gasket and head it will cool just like it would have in a passenger car or pickup.

The 727 that is behind a big block in a big motorhome will have heavier-duty internals and would be well worth swapping the correct tailshaft and housing.

These engines seem to be available in quantity with relatively low miles and make excellent starting points for high performance buildups. Low compression will be a problem but frankly it was a problem on all big blocks built from about 1973 on, and even earlier if we limit to 4-barrel engines. If you want to use the stock pistons and run regular gas you're fine. If you need a lot more power then you will be replacing pistons anyway so what is stock doesn't matter.

R.