Ive never actualy tried to rev it that high out of gear, will try this afternoon.

Fuel system is sorted, runs a holley red pump and holly regulator at 3-4psi at all times.

Thing about this problem is that it is continualy repeatable, it will do it in 1st after idleing for 20 mins, will do it in 5th down the main straight of the track after being held at high RPM's for ages, nothign seems to make it better or worse which is why spring pressure could be a very real cause.

As far as the distributer goes,,, heh, we have no one here that can recurve it, I run my A12 dissy (adapted to fit the A15 bracket) with and without vacuum (makes no difference really in power) I usualy run it at base timing (ie stock timing) I have run it -5 and -10 under base and obviously besides lack of power it still does the same thing at 6300-6400, with +5deg over base besides loads more power still the same miss at same RPM and with +10deg over base with race fuel it pulls even better but agian same thing at 6300-6400

Just for interest sakes, what type of timing do you guys run in your built higher comp A-series& how does it compare to the stock curve? I find the base timing works well on 97octane even with the medium to high compression... I presume you remove the vac advance to stop det at lower rpm with the higher comp?