Kinda LBC Related-Miata

If you blow a head gakset with 103 thou on the odometer, do you 
automatically rebuild the head?  Or are you worried like the old wive's 
tale that a new top end will cause blow by in the bottom?  The mechanic 
that is taking off the Miata head due to a pressure leak in to the 
cooling system says he does not like to rebuild the head at this mileage 
for that reason.  I'm not sure he knows what he is talking about.
Mike MacLean
60 Sprite
56 BN2
02 FLSTS
00 F-150
94 Miata
89 Nissan Sentra