~450hp from stock stroke 340?
For what it's worth, I had a stock stroke 340 built almost 25 years ago that made 480HP @ 6,3000RPM & 450TQ @ 4,800RPM, this was for a street driven 72 A Body with a 4,800RPM converter and 4.30 gears. Great motor, which would spin up quick and pull hard.
340 block bored 0.030"
Standard forged steel crank
KB hyper pistons & molly rings
OEM reworked 340 rods
MP 557 solid camshaft
Edelbrock heads, 60 cc chambers, mild porting, int 269cfm / exh 190cfm peak
Static comp 10.8:1
Edelbrock air-gap intake
Holley 850 DP
Really basic combo that was quick and surprised lots of Brand X guys.