427 / 454 Flywheel ??Difference??

Hey all , new to this forum. I hope i am clear with this situation. I work for a rebuilder who recently sold a split seal Marine 454 engine. On startup the engine shakes dang near out of the boat. I never had this customers flywheel, so i used a master flywheel i had to balance (454), and a brand new dampner also for a 454. We hot ran the engine an it performed beautiful.
We took the master flywheel off, and sent the engine to the customer... the customer installed and started it and all hell broke loose. I know that the 454 is externally balanced and vice versa...but does anyone know a distinct difference between the 454 or the 427 flywheel.

Thanks in Advance

Justin

Give the customer the balanced flywheel. Pandora's box just opened and she is not in a good mood. The gram weight difference is enough to make the bravest man quake in his boots.

454 takes an externally balanced flywheel and an externally balanced damper. Switch out either one for a 427 version, and you have a milkshake machine.

The 454 flywheel will have an obvious counterweight on the backside. The damper will too, on the inside.

The top picture is a 454. The second picture is a 427. The third picture is a 454 balancer. The 427 balancer doesn't have that large counterweight.

Most 427's are internally ballanced.Send him the flywheel you used and charge him for it.