Depends on the year. If the bus is running L-jet the 411 heads have no hole for the temp sensor 2 and if it's a 79 the bus exhaust won't fit (square ports on a 79 bus).
The major issue with all of them is domed pistons where the bus runs dished, the bus has quite a few more pounds on a 411 and the high compression isn't helpful. They'll go in easy, the dipstick/filler isn't a serious PITA especially if the bus is 73+ with the hatch over the engine, but the heads won't last unless you deal with the compression as the temps get crazy.
I guess you could shim the barrels up a bit but pistons are really the long term fix, if it's an old engine you'll want to ditch the head gaskets no matter what as they are a recipe for trouble. You'll want to use the bus distributor too.
