TTI are as good as you are going to get with regards to clearance unless you go with shorty headers or manifolds. I have TTI on my Cuda and I have never seen headers fit as well or as tight and my Cuda is pretty low. I have Schumacher Tri Y headers on my Challenger and they are awesome but they are no longer being made.
70 Challenger RT 440-6 EFI, 73 Cuda 416-6 EFI
05 Hemi Durango, 01 Ram 4x4, 14 Ram 2500 4X4, 10 PCP Challenger 6 spd RT, 01 Viper GTS ACR, 52 B3B w/330 Desoto Hemi, 70 Hemi RR (under const)
9 x Challengers. AAR Cuda, 4 RR, 2 GTX, 4 Chargers, etc... (too many to list)