Most guys arent fans of flowmasters on LS1s but that could be in the stock set up with a y and 80 series. I hear the single chambers sound good but its all in preference. The X or H just equalizes the bank pressure helps with scavenging and sound. Your prob fine with what you have. Its just details really. No doubt you have the room to work with so you arent limited with setups. A buddies 65 chevelle has the exhaust run like you described and I like the sound.
Trickflow As Cast 220cc 11.3:1, Yella Terra's, Fast92 NW 102TB, 98mm Lid, Kooks LTs, ORY, MSD, Hooker Aerochamber, PSI Custom Grind, Melling, Prothane/Energy susp, Spec 3+ clutch, Spohn LCA's/Panhard, Walbro 340
469rwhp 405rwtq.. Mustang Dyno