I'm putting the A15 back together & thought I'd use this other H2O inlet port due to it being a larger diameter (thought was more flow, less restriction)but looking at it closer the hose end is quite a bit larger then the stock A15 hose so that creates a minor problem but I begin to wonder if the smaller A15 stock one is like that intentionally to restrict flow to help get to temp faster?? I put in a 180 degree F thermostat.

This is also an H72 head, not the stock A15 head. I then out of curiosity took off the thermo cover on the A12 semi built motor I have (I didn't build it)to see if there was much difference between the 2 covers & they 'd actually restricted the flow even further by eliminating the thermostat completely, plated it off & drilled a much smaller hole - would a racing engine want this type of set up & why?

the motor



the head



Stock A15 intake on left, not sure what the right one is off, anyone know - its the larger port one...






A12 w/small flow hole...



thoughts anyone????