im testing an idea that poped into my head yesterday, i have a 82 ta w/a 355/th350 racing setup, now the problem is as usual running hot when running hard, i have a 165 stat and a direct drive cooling fan (non elec.) fan shroud, new water pump and freshly rebuilt motor/trans and still runs a lil warm on a 85+ degree day, gets up 220-240 dergree range, (keep in mind running above 5k rpm sometimes for that short shot hehe)
but anyway i gutted the center spring/slide assembly on the thermostat and just used the outter piece ( basically just an orfice plate) and it seems to be doing 100% better, maybe got up to 190-195 when running just as hard as when the thermostat was original. and then the temp comes back down to 175ish. so, sofar its a go and doing great, just thought id share

 

Yeah, you can buy those from Mr. Gasket and other people.. What I think you have made is simply a coolant restrictor that takes place of the thermostat..