No mention of the budget.
If he can find a junkyard Vortec 350 that's functional then he'll be the luckiest guy I know. A junkyard motor in 2021 is going to be an LS imho. Pay for the swap parts ($1500), microsquirt if non electronic trans ($500) and another $1000 worth of miscellaneous of crap. And yes, need to be somewhat ingenuitive.
Other wise, crate motor ($3K with related needed goodies), or hunt for a used, running Olds. Depending on what he can find in used Olds world, it has the potential to be the cheapest program available.
Everything pretty under the hood doubles the price. and If he fas to hire all of it done then triple the price.