Inliners International Forums General Discussion Engines 250 Exhaust Manifold Pipe Studs Gone...

It is possible to break the manifold if you crank down hard installing the studs. The unthreaded portion can split the manifold boss. I've not had this happen to me but I've seen it on other applications, specifically threaded rocker studs. In that case, the threaded hole in the head needs to be counterbored to clear the last incomplete thread or a hardened washer needs to be used to accomplish the same thing.

I would torque the studs to 20 lb-ft or so. No need for torque wrench just tight but don't crank down hard.