i recently installed a new chevy big block in my boat. i used the old balancer and fly wheel off the old chevy big block, the new engine has a bad vibration even when its at idle and not in gear. could the outdrive be out of alignment and cause this or do i need to start with the balancer and fly wheel. thanks

it sounds like you might have the wrong balancer and or flywheel ,can you give more info like what year the boat is and what year the replacement engine is?

I would think the balancer and flywheel need to be balanced together to the motor. Had to pull one of my 302's in a welcraft Nova once because the damn engine builder didn't balance one of the motors... I was not a happy camper.

all he said was he replaced his BB,like mike said we need more info on the old and new engine,,did he replace it with a 454 or 540 stroker? lol..

If it was not a 454 balancer and flywheel and from the same Gen 454 for a 454 then like said you got the wrong stuff.

The balancer and flywheel need to be balanced with the engine rotating assembly.

as like everyone said you need to know what gen 4,5,6 internal or external balanced?

I just love a good dyno.

If your old motor was a stock 454 and the replacement the same ,the stock balancer and flywheel should be fine ,,,without balancing to replacement motor . Sounds like you have a neutral balance flywheel on an external balance motor ..or vice versa.................Like everyone else asked ...what did you replace with what ...other than just a bbc

thanks for the reply's , i am waiting for a call back from the engine builder and will let everyone know