I did the 4ea 1/4" holes and they worked fine ... well ... they worked too good. I drove it a couple times in 50+ deg weather and I had problems building enough engine coolant temp. I was wondering if that was going to be an issue. I bought another thermostat (my 5th Mr. Gasket stat I bought and modified, I'll get it right yet
) and I'm going to do the 3ea 3/16" holes on this one, per Stewart Componant's recommendation and post results.
The short answer though is yes, it did eliminate the high temp spikes prior to the thermostat opening.
Dave