Compression Ratio Question - 10v N/A Engines

[Alan Kramer]

I have decided I want to increase the compression ratio some more on my '83 
CGT.  (I have already milled the head to the minimum specification.)  The 
way I see it my two easy options are:

1)  flat-topped pistons (w/ pockets of course)
2) change the shape of the combustion chamber in the head

#2 would seem like the difficult approach but I am thinking it may actually 
be easier.  The reason is when I built the engine, I know the pocket (in the 
head) is slightly concave and domed equally (by visual inspection) around 
360 degrees of the head.  I have seen some earlier heads which have only 1/2 
of the area domed and the other half is flat with the plane of the bottom of 
the head.  I would assume that the pistons used on these earlier (circa 
1981?) 2144cc heads are different (maybe they resemble the 2226's - deeper 
pocket) so the overall combustion ratio is in the ~8 to 1 neighborhood.  The 
pistons I'm currently using are stock 79.5mm shallow concave pistons.

So... my question is for those familiar with the older 2144cc engines:  Do 
the older pistons have larger pockets?  If so, then using the old head with 
the new pistons would give a higher C/R...right?  Then does anyone know at 
what year the shape of the head pocket changed?  (I also realize that it may 
be required to remove material from the pocket of the old head in order to 
keep the C/R from being too high...)

Thanks for any input!
Alan
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