Recently replaced my heads on a 350. Old ones cracked. Got some rebuilt units from a reputable shop with same casting numbers as old ones. Added roller tip rocker arms. Set up hydraulic lifters using method of rotating each cylinder in turn to TDC, then rotating pushrod between fingers until it was snug, then add a half turn of preload. After getting the mill together, and adjusting timing etc., it seems to have very little low end. Before the head cracked, it was very torquey....Did I set up the rocker arms incorrectly? :-\ They are 1.5 ratio units like the stockers they replaced....I think. Any Chevy guys want to set me straight?? The rig runs smoothly, just no bottom oomph! Ideas??