Balance

I bought a project car in pieces, one of which is a 454 long block. This motor is a Gen VI (cast into rear of block) and was originally a marine engine. (blue paint still visible on rear of block). There was no flex plate, so I ordered one from Summit, asking for a plate to fit a Gen VI with a T400 trans. Now that the motor is together and running, it feels out of balance. Does the fact that this was a marine application engine figure into this?? Could they have just sent me the wrong part?? Any theories would be appreciated!

You should have a 168 tooth flexplate designed for external balancing (eccentric weights welded to one side of the wheel) and a 1-piece rear seal. Here's the list from Summit.....
http://store.summitracing.com/egnsea...flexplate&x=23

What did you use for the harmonic dampner/balancer?

I'm using the original damper that came on the engine.

it is a good chance you did get the wrong one. you have the part no there more then one for 454

I kinda ran into the same problem with the 5.7 marine engine I'm using in the T. I had to pretend it was out of a '99 Chevy van to get the right balancer and flex plate. I hope I picked right, and won't know til I fire it up.

Don

I heard that the 454 H.O. motor has a forged crank and uses a different weighed flex plate than the 454 with the nodular iron crank. Both motors use the same front damper. Does anyone know which crank the marine engines use? I'm having trouble finding out the differences between marine, H.O., and standard application engines. Help!!! I wanna drive this car!!!!!