The improved HP was due to a change in the crank design also.
There have been several versions of the Ford V10
Original version years through 99
Improved head & crank (increased HP), put in the F series until the three-valve was introduced (2005) and in the E series through the end of the E series chassis production (2014, 2015, I forget now)
Then the 3 valve design, which has only been put in the F series chassis, they produce 365 HP
I and many MANY people owned (own) early production V10s with absolutely no issues. The reality is the plug problem was certain not common.