Thanks to all who replied to my note. I have a copy of a Clymer
Publication "MGA-MGB service-repair Handbook" which gives some typical
compression pressures for engines in good condition:
MGA 1500 130 psi
MGA 1600 135 psi
MGA 1600 Mark II 148 psi
MGB through 1974 160 psi
MGB 1975-76 130 psi
These would all be US specification models; shaving, decking, and
reboring would all increase the compression pressures. I didn't think
about a hotter cam with it's increased valve overlap. I guess that is a
possibility on my car; the car won't idle below about 1200 rpm, even when
warm. The engine doesn't have an identification tag on it; it does have
the early head without provision for air ports and the 5-main bearing
engine block. The valve timing marks on the sprockets are lined up
correctly. My compression pressures of 124 - 133 psi still seem low to
me.
Lew Dove
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