What intake should I get?
#18
#21
#22
Screw the COI and exhaust crap. The 97 4.6 does not breathe worth a **** internally. You need to get the inner air port working better before a COI will do much. It would be the same price for you to put on used P.I. heads from a newer 4.6 which should get you about 45 more hp conservatively. you will get no where near that out of COI and exhaust. Of course the heads are a bit of a project. And don't forget that if you put PI heads on a non PI motor it will bump compression to about 10 to 1. For me...(living in the mountains at high elevation), higher compression is a good thing because the thin air lowers it.
#23
The main reason I ran the S&B
#25
I know K&N makes one for your truck try for the '03 Navigator and that will broaden your options