It would be nice for the quench to be about .045 for best turbulence and combustion.This requires a mock up assembly to check it all out. and then machine the parts for proper clearance.
Like mentioned above,close clearance will lessen detonation depending on the head design,generally,smaller volume chambers are better at this.
The L series chamber is similar to a small block V-8 head design?Then an actual 9.5 compression should be maxiumum on 91 octane fuel with an iron head.
Building an engine that gives all it can give is more than just a lumpy cam and carburation,it's all the small details making the difference.
