X or H cross.

Same exhaust TTI 3" w H vs X.. X was a hot 340 , H was 410 Stroker. The 340 with the X pipe was a lot louder and had a deeper tone to it. Both were turned down at the rear axle. Both 4 speeds. The stroker would walk the 340 pretty easy. Cylinder pressure on the 340 was around 190 ish. The 410 was in the 175 range. 340 had 3.91 gears...410 had 3.55's, both had identical rear tires.
340 cam was HYD flat tappet 242@50 580 lift, 410 was solid flat tappet 264@50 620 lift