When I built a mopar siamesed bore hemi block,I started at 521 inches with a 4.5 stroke.
My builder at the time{RIP} Lou Vignogna tod me I would make more power with the iron block,,,,,,,,,I have iron

8363943-Al&Lou2.jpg (190 downloads)

HEMI-ITIS has no cure.
My condition is fully BLOWN!!