i used my plate to install and retain the plug. worked like a charm. the TDR piece located the plug and keeps it really snug. i would have liked to put a button on the front side of the plate to do the same, but the measurements to locate the center of the plug was killing me to do with the trans and block in the truck. alot of folks with the plate are just using a piece of 4" flatbar bolted into place with great results. so i went with that.

 

Glad you got her back on the street Chris, now get to the dyno and give us some #s.

 

Check out the H2O pressure thread. We've been talking about this for a while.

The problem is too much energy into the cooling system and the delay in the tstat opening. I think the best fix for racing would be a manual valve in place of the tstat that could be opened at the start of a run. A bandaid would be to put an expansion tank on to absorb some volume and stop the extreme pressure rise. Also a bigger relief into the coolant recovery bottle. That little 3/8 inch tube is not enough for these conditions.

Wetspirit

 

Replacing the thermostat will not do much good for you, the head gasket coolant hole's are orifice's for controlling the coolant flow from the block to the head, if I was having issue's with freeze plug blow out , I would stick a press. gage in the coolant plug right next to the oil cooler cavity on the block, you will get a lower reading if you check it from the head coolant port.
the ISB has a max. lower block press. of 57 psi with thermostat open and radiator cap off. generally there is about 25 psi block coolant press.