Today, dollar for dollar, is the 318 faster than the 340 ???

Just to kinda slide/make a point the mopar crate engines used new production line engines. Then when they quit producing the factory engines they started using remans. And made pretty good reliable 380hp engines.
And not just mopar done that

The only thing I would be worried about is the head work on the guides.

The thing alot of people are leaving out is that forged pistons are hard on cylinder bores and have alot shorter life span. $3000 can be done reliably and make pretty good hp. Factory has been doing it for years