Don’t bother with a destroked 340. It’s going backwards for the most part. You want a mileage car that runs 13’s? Take that 340/360, add a small cam with a 4bbl, run an OD trans with 4.10’s. Enjoy…..
Your next post is confusing since you want an engine turn 7500+. That makes no sense to running the above ET. Over reving? Rev limiter. The engine stutters, you shift. Problem solved. Case closed.
You also need to turn the right rocks over to find the parts you need for a all forged 372. It’s not that hard to do. Expensive that way. Part by part.