Wondering what the intake & exhaust seating pressure is.

This is a S.III 4.2L

Also, wondering if there are any other OEM cams that may be able to unterchange & give a little more lift & duration.

 

178-E Camshaft - 3.8 - 4.2 Six Cyl - Kelford Cams


1300$ Cam and springs.


Also try webcamsafts. They can grind up just about any cam...for a price.


Read this from page 63....
How to Power Tune Jaguar XK 3.4, 3.8 & 4.2 Litre Engines - Des Hammill - Google Books
Spring pressure is on the bottom of page 67

 

The factory Cams aren't going to be that great for boost.

Those valves are designed for a NA build & for t offer enough seating pressure, so we're gonna have to shim the OEM valves, or see if there are any other conparible springs from another engine that we can retrofit.