[67 455 Bird ragtop]

I just want to make sure I understand WHERE you drill. If I understand correctly you drill the "plate" that is basically the base of the stat. This is the part that covers the openeing in the manifold. Not the covering around the valve in the center of the stat?? Or did I get it backwards ??? ( Probably)

[Bad Karma]

You are correct its the plate. The flat thin metal outside the valve. Hope it helps.

[60man]

I tried that (drilling holes) T-stat mod a while back on my race car to replace the restrictor since I had blocked the stock bypass passage.. If you drill the T-stat your bypassing it while valve is shut. No need for bypass hole from intake to timing cover. I blocked the passage with a small piece of flat plastic behind rubber o-ring.
This forces ALL the coolant to pass throught the radiator rather be bypassed back into motor. It did improve my cooling while siting in long staging lines such as Norwalk..........
Just plug it next time you pull intake...........

[Tom Vaught]

I will post a couple of other cooling ideas once I get them written up concerning by-pass strategies.

Tom V.

[Nickv]

Originally Posted by ctgross

Hey NickV, glad it worked for you too What temp. range thermo. are you running? I used the 160, just wondering if it works just as well with..say a 180/190?

I'm running a 160 thermostat

[Tom Vaught]

Had a little more time tonight.

I have used three different methods to by-pass around the thermostat for additional cooling, (I still put two 1/8" holes in the edge of the stat to purge air).

On a tri-power intake, I have added a fitting on the waterneck part way up the length and connected a by-pass hose to a unused opening in the water cross-over. I put a restriction in the line to get the waterflow I wanted. Putting one in the fitting works too.

On 4 bbl intakes I have used a Moroso thermostat "chimney" and added a bypass hose to the same manifold location mentioned above and then either used one of the drilling in the part or added a new one to connect the hose to.

The third method I have tried once but liked a lot was to add a by-pass hose from the cross-over to the top of the radiator tank. I could by-pass a lot of water with this deal and was able to find the "sweet spot" in flow for the engine I was working with using a ball valve for the restrictor. Have no idea what the actual orifice size worked out to but it was worth doing.

Tom V.

[Herb Hagan]

I just went thru this recently as well...I would recommend that instead of drilling holes it is better to grind the perimeter of the thermostat w/flats @ 120* intervals. I did this with a bench grinder and don't have to worry about drill chips in the thermostat. The water will flow around the outside of the thermostat and there is still enough material left for the the thermostat to register in the counterbore/goove of the water crossover.

Herb

[Bad Karma]

Originally Posted by Herb Hagan

I just went thru this recently as well...I would recommend that instead of drilling holes it is better to grind the perimeter of the thermostat w/flats @ 120* intervals. I did this with a bench grinder and don't have to worry about drill chips in the thermostat. The water will flow around the outside of the thermostat and there is still enough material left for the the thermostat to register in the counterbore/goove of the water crossover.

Herb

That sounds like it should work fine also. If someone doesnt have a grinder they can drill or vise versa thanks for the input.