340 J-head flow rate ??

hi, also test pressures are a factor!! a motor doesn't see 28 ". 25 " is more realistic. I imagine that 10" would be more in line. testing at various pressures
is an eye opener. bore adaptors will change flow also. also to get the max from heads , all ports need to be tested. there could be a dead port amongst the good ones, in same head. I've flow tested and seen this before. one of the most important numbers is the port velocity. it fills the cylinder!! as Mr Betts, commented, don't get hung up on the big flow numbers, port velocity and port shape are most important! velocity is what fills cylinders. just food for thought.