[Dick Boneske]

This restrictor is intended to save the heater core from sudden peaks of pressure when the engine revs higher than normal. I know that I've experienced several failures of heater cores since I've owned my first '64 GTO in 1964. I have not had one fail since using a restrictor in the small (pressure) hose.

I have tried 1/4" and 3/16" sizes. The operation of the heater doesn't seem to change with those sizes. I get adequate heat with the smaller hole. For all I know, a 1/2" hole would prevent core failures, but 1/4" or 3/16" works fine.

I really don't see the need for further discussion unless someone has their own experiences to add.

[tempest1964]

Thanks for clearing that up Dick. I've never done this mod before, so it benefits me to discuss it. I appreciate the more knowledgeable members like yourself taking the time to explain things to guys like me with less knowledge/experience.