Car ran slower then expected.

Initial timing? My guess should be around 20-24 degrees minimum with that camshaft. Fix the mechanical to hit your total number. Then curve it using lighter springs.

I'd bet the carb is going lean.

Pull a plug and look. If porcelin has got speckles on it, too much total timing. Running closed chambered Ede headed? They tend to like in the 32-34 range, especially on std pump gas. Yours may be different, that's the range I've seen that works well.

As mentioned, figure out why it's missing, laying over.