online place to buy 5.0HO?
Reply #21 –
That was basically because Ford's advertised horsepower amount was wrong.
There was a recall, and these were the pieces that were put on.
Hence the term "PI"...I guess in a way, it could be said they were a "higher output"..but were not officially named as such.
"The V8 remained untouched, while the Cobra claimed 320 hp (239 kW). Ford responded to complaints by issuing a recall on the 1999 model Cobras, which were given computer, intake, and exhaust improvements, to match the original claim of 320 hp.
As a result, Cobra production was halted in 2000 (except the limited Cobra R) while the company was developing new parts for the missing power. The changes were incorporated into the 2001 Cobra, which could achieve 1/4 mile times in the mid-13 second range."
"As a "modular" family, the heads on the earlier 4.6 L SOHC motors can be exchanged with "Power Improved" heads as offered via the Ford Parts Catalog. Due to a different combustion chamber and pistons, the compression increased to over 10:1 and subsequently required premium fuel to inhibit detonation (knocking)."
This is from that same wiki link