AFR MOPAR 340 HEAD TEST!

LOL keep trying... stock 340's off the assembly line weren't 10.5:1 If they were 9.7, you got a decent one.

Mazz built that engine. You have no idea what was done to it. Any clean up porting on the heads, std or offset adjustable rockers corrected for ratio. Not knowing the small details makes it a loose guess as to why it made that hp level. Anyone that has raced and built stuff to the small details knows what a difference getting the TRUE rocker ratio/lift at the actual valve creates. The typical ratio of 1.43 using stamped rockers and shitty pushrod angles are rough on SBM engines.