David-
Wow, where to start...
Gasket-
Yes indeed open up the holes in the gasket which seem to be binding on the
studs. You should find that it will only be a few of them. Do not enlarge all
the holes as the gasket can then move around before you torque it down as the
studs locate the gasket. When the gasket is merely forced over the offending
studs and the head torqued down, the gasket will actually be found to have
been pushed up the stud hole in the head upon tightening. This leads to very
poor sealing.
Always install the gasket with the lettering (or numbering) up, unless the
word top is stamped on the other side (never seen this, but anything is
possible).
The steel shim gaskets come in two styles. The original Stanpart unit was
for an 83mm bore, but later repro gaskets are the right size. If you have one
of the early gaskets, it will need to be modified. Check your comp manual as
I think it describes this, if not, what you have to do is to remove the
innermost "ring" of the gasket on each cylinder, and a little more at the
intake valve side. You really need to use some sort of high speed grinder
(dremel) to do this. Do not use a file as you will only ruin the gasket (yep,
thats experience talkin there).
Compression ratio-
If you have already cut the .080 off the head, don't go any further. You
have to remember that the theories put forth in the comp book assumed decent
gas, alas a thing of the past. The TR4 head does not have the best combustion
chamber design and the flame front gets sort of "hung up" for a bit around
the spark plug, before it burns across the piston top. Figure on putting back
quite a bit of the original "ramp" across from the spark plug hole as this
tends to "mix up" the combustion gases a good deal, which in turn will help
to move the flame front better (lessens the probability of
pinging/detonation).
While you're in there you should also "eyebrow" cut the liners to allow
better breathing, especially on the intake side. You can cut back almost one
half of the thickness of the liner without any grief. Stop the cut about 1/4"
from where you see the ring stops in the bore. Do this with a file and then
smooth and polish with sandpaper (the liners will file surprisingly easily).
If you do all of the mods, your chances of pinging will be decreased,
hopefully to a point that you can live with this setup on the street.
Other thoughts-
You will probably find that the stock carb setup is not ideal, and going
to richer needles will really find a lot more power (try RF needles if you
can find them, they worked best for me with a similar setup).
Your advance curve may need some attention also. As distributors age,
they usually tend to allow full advance at an earlier rpm range than
originally (the springs tend to loose tension and the weights get sloppy on
their anchors). If your weights check out ok, you may want to take your
distributor down to your local hotrod shop and have it further modified. If
you have a pinging problem (unix users aside), try using less initial advance
and set the distributor to advance a little slower, with total advance not
coming on til over 3000rpm. You can play with this even more, moving the
advance up further and even increasing total advance by grinding the "tail"
off of the cam.
The Car Curmudgeon
Nick in Nor Cal
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