Blueprint crate engine

Personally.....
Imo, I'd buy the lesser version of the 408, and plan on using the savings for a aluminum case 727.
Better yet!... a 518 overdrive swap. (Find out what gear is in the 8 3/4.)
You do want to drive this, yes?
(I'd use the Iron two speed for keeping my trash can from flying down the street in the wind).