They are going into the crate engine business. I can understand some "more money than brains" type buying a QC4C for a street rod, its already being done as I write this. And I can see some custom supercar company like the old Vector using them as a optional engine.
But they will also be selling the higher end, conventional BBC based push rod engines as well. They are a million miles from being competitive in that market. Unless they drop the price considerably and sell them without the warranty. The warranty is about half the cost of a Merc blue motor. Not sure how they are going to handle warranty and "scheduled" service and rebuilds to maintain warranty if there is one..
At 750.00 per HP, there are better options, but bling has its price.

But I can't imagine how they are going to sell push rod engines for anything near the price they sell them for to boat builders. They'd have to be dipped in 24 carat gold.