There are pluses and minuses. The more caster, the higher the self-centering effect and associated steering effort. Which can be a benefit on-track with the driving style that likes more caster.I take it "the more caster the better" when it comes to a foxbody and go with as much as I can get?
There is also more camber change when the wheels are turned. So it kinda depends on wheels, suspension., tyres, driving style, etc.
Rethink - you've got the negative offset front a-arms, right? Then you'll probably not get much past 4 degrees caster. I have the standard arms and with the MM k-frame that gets my car to about 6 degrees. If I'd gone with the +0.75 forward offset arms, that would take my setup in the 8 degree range, iirc. Mercedes territory.