I have two 1275 heads from which to choose: One is fairly rusty but cleanable,
a newer version (sculpted surface, Vizard p170) with a standard casting number
12G 295. It is apparently unmodified, with small valves, although it looks
like there may have been a little reduction in the guide boss. I have not yet
taken out the valves (no spring compressor), so it is hard to tell.
The other is in good condition but apparently older (flat surface, Vizard p169)
with casting number 12G 1316, which I have not yet been able to find described
anywhere. It has much larger valves and has been shaved roughly 0.068". Dema
Elgin says my cam (one step above Cooper S) should not use a compression ratio
greater than 9:1, so it is possible that this head is shaved too much.
Similarly, I have two cranks, one rusty and one clean. Neither is obviously
modified from stock (crank journal 1.625"). Both have holes drilled through.
One is marked B1 and the other P1, the meaning of which I have not yet found.
And I have two blocks, both reasonably clean. Both are 12G 1279 with
miscellaneous other numbers (2 155 103MD, 1 184 10L), the meaning of which I
have not yet found. They do not look different to my inexperienced eye.
Any thoughts on the relative merits of any of these pieces to be modified as
necessary for a "medium" level of upgrade?
Michael Rowe
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