cant gap plugs bigger then 0.23" but why?

[spools420a]

Car was gapped at 0.30" when i was runnng stock t25 on redtop,after installing generic 2871r/550cc/walbro pump/enthalpy ecu/z32 maf and the plugs are NGK BKR7E.the car would buck under boost.to fix this i had to tighten the gap,the most i can run is 0.23" but why?

since this happened right aftter the 2871 swap and was running fine on stock gap this says its not a issue with compression or engine but somthing with the turbo upgrade.

afr are at 11-0 - 11.3 at full boost 15 psi on 91 octane

i put a spark tester and tested the spark from each coil and it has no troubl jumping a large gap making a nice crisp snap and nice looking spark,that tested perfect.

I feel that such a tight gap will make me lose some of the power,is this normal to have to gap this tight?would leaning the mix a tad help you think to maybe 11.5ish? we only have 91 octane here so im trying to stay in the safe zone.if its normal to have this tight a gap then thats great but shouldnt i be able to run closer to 0.28"?

note: i posted this on another thread and appologize for having two topics on this but i cant delete the thread as i intended.