Is there really that much difference between the pi heads and the non pi heads, my 2001 f150 4x4 4.6 has the pi heads and I raced my friend in his 2000 f150 4x4 4.6 and I smoked him it wasn't even close. My truck can also smoke both tires with a open diff. We both have the 331 gears. Btw my f150 hangs right next to a modded mustang roller and camed 302 bronco

 

I think there is a 20hp difference. Torque curve is probably a bit different as well.
3:31 gears are not exactly ideal for off the line performance in a 4x4 truck...


I dunno how your hangin with a modded stang..?
I was a bit surprised to see myself pull a half truck length on my brother in is 05 dodge 1500 4x4 with the hemi. He crept on me around 45-50 and eventually passed me, but I had him from a roll. I was running 33x12.5's too with 3:73 LS. I dont race my truck much... but I know it has what it needs when I need it.

 

Its not a mustang its a 89 bronco with a 302 mustang roller motor with a after market cam, It does have a 4 inch lift and 33s 355 lsd.but yea my truck jumps off the line even with the 331s, I figured he'd smoke me but we hung side by side. I just don't like it when people say the 4.6 isn't a good motor cause mine has plenty I like that it can get decent gas milage anyway haha thanks for your input man