Just purchased a Cloyes 9-3100 timing set from Summit for a 355 I'm building. I was surprised to find the .250 rollers are split, versus 1 piece. I've read the Cloyes 9-3100 has a True Roller Reynold 9-130 chain which has a concentric ground split roller pins. The pins in the Cloyes 9-1100 are extruded solid roller seamless chains and are not ground true. Both are .250" O.D. rollers. The sprockets used are the same iron cam sprocket and steel crank sprocket for both timing chain sets but the 9-3100 set is hand matched. There is a a $60 difference between the original "race" 9-3100 and the "street version" 9-1100 so I'm wondering if the supposed chain upgrade justifies the $60 additional cost. Application will be solid roller or flat tappet hydraulic as I haven't decided yet, either cam will run double springs.