Machinist buddy of mine pointed out that the after market heads don't have the extra bolt hole that the stock exhaust manifolds need on a 1988 GTA. I seem to be running out of options for a decent head

 

Why spend the money on good heads and then choke it with stock manifolds? You can get emissions legal shorty headers that flow good and keep good ground clearance.

 

well maybe because the reason I am doing the same thing. To keep it looking stock but bump the engine a little.
I am with you on the choking part... and headers could add 30 HP all alone. But... looks have something to do with it to.
I would like to see how this one goes and if someone does make a 7 hole head.

 

After researching what's available on ebay, there seems to be quite a few aluminum heads with the 7th hole, but with questionable quality. What I did notice is that the angled plug heads will interfere with the #5 cyl. with the stock manifolds.

 

http://www.goodson.com/technical_sup...ing/CHC-10.pdf

You could give this a try and let us know how it works.