Sorry about the false information,your right about the 351w. The 2000 Cobra R had a 5.4 V8 in it.
And I have checked the VIN tag on my rear diff housing and on the inside door jam and I definitely have a 3 27. The tag on the pumpkin reads 515D 3 27 88 3M17, I don't have trac-loc though. If it had track lock then it would be 3L27 instead of 3 27.
So MadMikey you think a PI motor would be a better baseline then the DOHC from a Mark VIII?
Also, if I was going to stick with a 2V which is better? 1: PI heads ported or 2: Trick flow heads