seven4nineR wroteRereading the great info on that page one of Brad's notes stands out: "Advancing the inlets gives more midrange and less top end (therefore implying retarding the inlets gives less midrange and more top end)."
and just before that it says "Next - a generalisation."
but if it is at 104 i'd say that's too advanced for the capacity.
this one was at 114 -
http://www.bikeboy.org/996SPS.html
i don't think it'll need much different ignition advance curve, unless that eprom is different to the std. they generally didn't change it much (at all) back in those days, and a 916 p8 eprom usually goes out the top around 39 degrees. a couple of degrees either way will make fuck all difference. might be worth see if it's stupid all the same.
the 853cc 748r i did is here. same 104./108 cam timing -
http://www.bikeboy.org/853rstuff.html
your torque peaks amazingly early for a 4v. a std 996 peaks similarly around 7k and again at 8 ish, but it's low for a 926.
i'd get someone who knows what they're doing to look at the heads.
or piss those high mufflers off with those long pipes. see if that helps. it's a long exhaust. i don't think 45mm headers are too small, and i've seen st4s make easy 120 through a std header set, but 45mm pipes that long out of the cross over to the mufflers strikes me as not good. i'm sure a good spag system would be better. steve's is a non cross over system with a short link pipe from memory. maybe try something like that. cut the st4s front header same length as the rear header and start going up in steps until you get to 50mm and go at that into the mufflers.
you could bore the bottom of the throttle bodies out to 48.5mm or so. 46.5 is std from memory. that's nearly 9% more flow area. how big are the inlet manifolds under that? then again, the 853r i did had std 44mm outlet diameter from memory. don't recall now. it had 45mm headers too, into a 45/50mm half system.
