Drilling the thermostat??

[undy]

I've done away with my cooling water bypass line that ran from the intake to the water pump suction, common to all FEs. It's been plugged on both ends for some time now. I've never bothered (should have) to drill the thermostat to maintain flow across the engine when the thermostat is shut. For not doing this, I've suffered some time now with high coolant temperature spikes prior to the thermostat opening. Convection, not flow, getting the hot coolant to the thermostat's thermo bulb takes too long, hence the temp spikes.

The solutions to this are four fold, take the thermostat out, install a restrictor plate in place of thermostat, reinstall the coolant bypass or drill some holes in the thermostat. While not going into the merits and draw-backs of each, I chose to drill the thermostat. My question is, how many and what size holes do you guys recommend?? I've Googled my arse off on the subject and what I've found has led me to 2ea 3/16" holes.

BTW... I'm running the Robertshaw high flow/balanced t-stat, which I'll drill the "balance cup" that actually opens, not try to fit the holes in the perimeter ring. The thermostat is also marketed by Milodon and Mr. Gasket, all the same t-stat.


Just in case you're wondering .... why?? The factory bypass actually recircs the water through the block, bypassing the radiator. This facilitates a quicker reheat at the loss of a small amount of engine cooling. While this does not present a problem with the average vehicle (due to designed massive cooling system capacity redundancy), this good be the proverbial straw that broke the cooling system's back with our "cooling system challenged" Cobras.