id go 3.55. once you add drag radials, the 3.15 basically sucks down low. from a dead stop expect some bogging especially with the GT350 manifold and Cat Deletes I had. and this is with both Lund and an AED tunes.
the shorties gained you 0. The car has quite an effective "Shortie" from the factory. The cats are the restriction.
If you are still on a quest for power, the only suggestion I have for you is to buy an SCT X4 or nGuage and a get a aftermarket tune (AED, Lund, etc).
I understand the...
https://performanceparts.ford.com/part/M-9424-M50CJA
vs
https://www.americanmuscle.com/cobrajet-intake-manifold-1113gt.html
Is the lid the only change?