As some may know im swapping out my blown motor for a PI swapped motor out of a 98. I have heard that the 98 motors made a little more power than the 96-97's, is this true and if so why? thanks.
PI cams and intake and you are pretty good as far as the HP bump. The PI heads are minimal at best for increased power. In the 98 you should be at or above 240RWHP.
Some places I've seen the extra 10 hp in the 98 GT attributed to the headers. In other places it is attributed to the EEC and an "upgraded fuel system." So for which one it actually is: