> Interestingly, when I showed the head to my
> machinist, he said he could clean the head without destroying those tubes.
Most cylinder heads these days are made of aluminum, so most hot tanks
that are used to clean up heads tend to use an aluminum friendly
solvent. Any place that can dip an aluminum head should be able to
handle a late 4A head without problems.
Which gets me back to heads. Only the last version of the TR4A cylinder
head had aluminum push rod tubes. All prior cylinder head versions had
> He had asked me if I wanted to mill the head when
> I mentioned I had a set of 87mm pistons
The TR4A head was designed to give 9:1 compression with 86 m pistons.
Going to 87 mm raises the compression ratio just slightly.
The dumb question is what kind of performance do you want, and what kind
of gas are you willing to pay for.
For a street touring car I suggest no more than a minimal shave to
insure a flat bottom mating surface.
If you want a performance engine you start getting into the realm of
opening up the intake shroud pocket. milling real metal off the bottom
of the head to make up for it, grinding eyelashes into the top edge of
the sleeve and playing games with the head gasket. It is far easier
just to keep things stock at 9:1.