[TedRamAirII]

Originally Posted by Don 79 TA

the high flow balanced sleeve type of stats like the Robert Shaw 330-xxx have an air bleed in them and an arrow indicating which way it should be installed, usually towards the front rad
it helps burp the system and acts a very small by pass without causing excessive cooling or reduced heating for those that need it
http://static.summitracing.com/globa...0-195_w_ml.jpg

here is one with some holes drilled in it
http://static.summitracing.com/globa...p-300_cp_m.jpg

I dont think position of a bleed hole matters on a Pontiac thermostat that is mounted flat. A lot of engines have them mounted vertically so yes, that would matter. A 1/16" hole is plenty. Its going to open and self bleed anyhow. But everyone likes an edge. ; )