From the factory they were under-torq’d. Toyota had a recall to increase the torque to around 72 ftlbs. I don’t remember the exact number though.
Aside from that, the next biggest destroyer of the stock Head Gasket is Detonation. This happens because people turn up the boost without having supporting fuel mods and/or a good tune. Every car is different; but, once you start getting into the 14psi range with a stock fuel system and stock HG, you are risking a BHG.
With all supporting mods AND a good tune, good power can be achieved with an OEM HG.
So, I wouldn’t necessarily say that the 7M HG is bad. It just HAS to be done right! No exceptions!
Aside from that, the next biggest destroyer of the stock Head Gasket is Detonation. This happens because people turn up the boost without having supporting fuel mods and/or a good tune. Every car is different; but, once you start getting into the 14psi range with a stock fuel system and stock HG, you are risking a BHG.
With all supporting mods AND a good tune, good power can be achieved with an OEM HG.
So, I wouldn’t necessarily say that the 7M HG is bad. It just HAS to be done right! No exceptions!