What would you build if limited to 372ci - with boost as an option

Yup. And were I building your engine I’d be worried about piston length.

Can you ballpark an appropriate rpm the cars in your class run?

Since you want to reset a record I’m assuming you want to be competitive so that’s why I was explaining why tall decks and short strokes cause issues you might not have thought of.
of, sorry. It is all over the map. Depends on your set up. I had pictured a 6500rpm engine with boost. Maybe it would last a while, vs 8000rpm. Hp and gearing. So, if using a 28" tire, 2.5:1 ratio with a max at mile 4 and sustained for 1 mile