I'm no expert, but from all the other postings that I've seen over time the Performer intake is probably choking your engine. I have a Blue Thunder intake and all fit under the screen (barely) when I was running it.
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.