If it won't rev past 5500 then there are other issues other than a lack of boost!
Is the air filter clean? Plugs new and correct gap - circa 0.75mm should be ok here, maybe a bit more if you have platinum plugs.
Check the cam timing including the dizzy position. Gaps on phase sensor and CPS should be .6 to 1mm IIRC.

Does the Amal valve click when you switch the ignition on?
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who's stage 1 is it?