no,you need the drilled&tapped holes in the flywheel for bolting on the drive hub,unless you go with a omc drive hub,it bolts on with studs that also bolt the flywheel on.absolutly nothing wrong with using a heavy flywheel,mercury marine sold a million of them that way.

i did not know and have never seen a internally balanced 454 from the factory,ya learn something new every day!

Pretty sure they didn't.

I think they just list it that way since 427 stuff isn't searched for much.

http://paceperformance.com/i-6255729...utch-only.html

3991469

DESCRIPTION
This 14" diameter manual transmission flywheel accepts a 10 1/2" and 11" diameter heavy-duty clutch. It can be used with all internally balanced Chevy big-block V8 engines. Technical Notes: Do not use with externally balanced 454 ci engines. Use with neutral balanced damper P/N 3879623. 168 tooth starter ring gear. For use with Mark IV engine only.

Doesn't surprise me at all. Honestly I think all those stroker assm kits should be internally balanced. I would never trust an already so called balanced kit anyway but that's just me. Easy to drop off flywheel and balancer at machine shop to have them neutrally balanced.

OP should contact where he got it from and just confirm what is what and go from there. He might get lucky.

that is why i asked him to post his rotating assembly part number,i was going to attempt to gather information about it but no number posted.

Scat Series 9000 Cast Pro Comp Stroker Lightweight Crankshafts 9-454-4250-6135L

Can you feel the vibration in the boat when it's running?

yeah it shakes pretty bad....I thought I had a miss or valve train issue but after inspecting every checks out.

the listed number is not a rotating assembly,it is a crankshaft.not knowing the rest of the parts used in the build it is probibaly not balanced,pretty obvious if the engine is shaking.time to remove engine and get the rotating assembly balanced.

Just from my build, I went with the eagle forged crank kit. I went with the externally balanced. My machine shop recommended what flywheel and balancer to go with. I had him put it together and balance everything. I know you already have it together but I would take it to a shop. You can't beat having proven data that it spins smooth and all the clearances check out. Also I found all dyno guy that was 500 to run it for 4 hours. In my opinion the everything Xtra $ spent is all for the piece of mind. This way I know that it is together and running correctly. This way I don't have to build it again and spend 10x the amount I spent to do it right the first time. Again just my opinion but pull it and spend some money to save a lot of money.