I just had a ootb TF190 head on the flow bench.
My numbers are very close to the advertised numbers on the intake side.
My exhaust numbers are lower, but their test used an 1-7/8” flow tube, I used no tube.
Tested at 28”, 4.00” bore:
Lift——I/E
.100– 66.7/51.6
.200–133.2/109.8
.300–200.8/154.9
.400–251.3/184.7
.500–281.2/198.1
.550–289.8/200.5
.600–295.4/201.7
.650–293.5/203.0
.700–292.4/203.7
Intake flow starts to sound a little raspy from .600 and up, and loses a few cfm.
Exhaust port is pretty quiet and steady.
Looking at the port in person, I wouldn’t have really expected it to get that close to 300.