Chris, there is something I wanted to run by you and thought others may be interested. A lot of times we figure that if a part worked before our mods, it should work after we're done. I think the radiator cap is a good example. It's pretty much kept wet and lubricated for the life of the car, but then we go and drain the radiator and let it sit for weeks or months in a box while we change heads, or swap engines or something. My theory is that this is when my cap went bad. It just dried out. Mine was in a box for a good 4 months.
Just thought I would mention it and see what you think.
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351W 89 Mustang GT Convertible