Look on the front of the heads (behind/below the alternator) - if there are 3 parallel bars cast into the surface they're GT40's; if there are 4 parallel bars, they're GT40P's.
I don't find them overpriced at all, in fact, $300 is quite a bargain for what you get, or, conversly, $220ish for stainless is a great deal. From what I understand, you'll pay nearly $300 for a set of mac's that are p compliant, and we all know Mac's are barely worth the money you'd get back from recycling them as scrap metal. The next best thing, jba's are well over $400-600+
I have JBA shorties now on stock heads looking to upgrade to Gt 40's.
Are you saying my shorties will clear the Gt 40's from any spark plug boot problems like the FR shorties will? If so that would be so cool. I can just buy the heads and intake and keep it moving.
Let me know
If I had to choose between the two I would get the P heads. It may cost more for the headers but if your already going with stock heads you might as well get what you can out of them and the P heads flow better.
If you want over 300hp and you probably will, I wouldn't bother with them.