Timing Chain & Sprockets: 64-79 Pontiac V8 Double RowDual Row timing chain & Sprockets for the PONTIAC 326, 250, 289, 400, 421 455 Pontiac V8 engine. Mainly Comp Cams brand or Isky or similiar top notch brand. SPECIAL NOTE: One reason why Pontiac's are easier to work on then Chevy's. Pontiac timing chains are a breeze to change since the balancer, and timing gears come off without the use of pullers. Also installing the timing cover is a breeze since you don't have to loosen up the oil pan [like you do