After all new valves, springs, guides ect., I'm reinstalling the head on my 52 Buick Special with the 263 straight 8. I reinstalled the studs that hold the intake/exhaust manifold on. When I did so, I threaded them in until they bottomed out in the head. Now that I am trying to reinstall the manifolds, there doesn't seem to be nearly as much thread to install the nuts on the studs. I don't have everything tight, so there is still room for gasket compression ect., but it just doesn't seem like enough thread. I can barely get the nuts started. The threads on the head side are 3/4" and are fully seated in the head. Is it safe to back them out a 1/4" or so so that the nuts can fully thread onto the other side of the manifold? Is that was done at the factory?
Rule of thumb, you need 1 1/2 times the diameter of your bolt for depth of thread engagement...eg: 1/2 inch bolt needs 3/4 of thread depth to properly hold...so if you have 3/8 inch studs, you need 9/16 of threads in the block...does that help?...
That does help. I guess they won't work their way loose, it just seems sketchy that they would be only partly threaded into the head.
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