> Jethogger wrote:
> > Hello JOHN, Early 70's MGB head. The letter "L"
> stamped at the rear. Had bigger valves and no water
> return hole for the hot water chokes. Have one on
> > my 67B I am building.
>
> John V. replied:
> That's just what I was wondering. Thanks.
Gents ... the early 'B'(pre 18V) cylinder heads have
1.58' intake valves and a 43cc combustion chamber ...
the later 'B' (18V) cylinder heads have 1.625' intake
valves and a 38cc combustion chamber. To produce the
later head a larger kidney shaped combustion chamber
was utilized, in lieu of the heart-shape of the earlier
head, to accommodate the larger intake valve ... to
maintain the CR the chambers were shallower and the
thickness of the head was reduced ... the reduction in
head thickness required that small cuts be machined in
the top of the block to prevent the exhaust valves from
contacting the block. *Do*not*fit*an*18V*cyl*head*to*
*a*pre*18V*block*unless*you*have*the*appropriate*cuts*
*machined*in*the*top*of*the*block*. Don't forget the
differences in combustion chamber capacity as they will
have impact on your CR.
John V. ... the 1622 uses the early 'B' head.
Safety Fast! ... larry.g.unger@lmco.com
'61 MGA 1600 MkII
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