I thought you can't bolt it on wrong but Tyler Crockett was telling me a similar story last month at his shop,I am going out to work in shop and Ill look and see,Smitty

I just looked at a mk4 flywheel,if crank didn't have a alignment dowel and you don't line up the dowel hole in crank to the extra hole in flywheel you could have 6 possible ways it got bolted to crankshaft as the holes i just measured are evenly space. If thats what happened it would be out of balance worse than one that had no weight when it was suposed to have one,Smitty

WOW, I just looked at my old crank and there is a dowel on it. I was thinking to myself when I installed the flywheel this is kind of odd.

So the flywheel/crank the bolt patter is not off set?

I wish I had a flywheel laying around so I could see this with my own eyes
Thanks
JIM

The flywheel pattern on a mk4 style crank is not offset,when i checked for you this morning i measured from hole to hole with vernier calipers on a 454 mk 4 flywheel, then just to be sure i layed a auto-matic flex plate on top of flywheel lining up crank bolts,they lined up. Then i turned it one bolt hole,they still lined up,then i turned it one more bolt hole,they still lined up,etc,etc.It will suck pulling your motor out of boat after just finishing it but if this is the problem it will be easier to fix then pulling motor out THEN having to tear it down too. Good luck,let us know what you find,Smitty

If you have a set of calipers,measure hole to hole on your old crank,you'll see it then,Smitty

i did the same thing and had the same problem. the 454's are all external balance motors and the flywheel and harmonic balancer are counterweighted, the 496 kits are internal balanced and you have to run a neutral balance flywheel and balancer, the stock stuff will absolutley positively not work...look at your old balancer and flywheel and you will see the counterweights on them.

Smitty you were correct

I pulled the engine and that is what I found. I was smart enough line up the paint marks on the flywheel and the coupler but got in a hurry and was not thinking about the flywheel and crankshaft.

Anyway the engine is running like a deer.
Thanks for your time. These forums are PRICELESS

I'm glad you didn't have anything serious,Smitty

By the way the big valve relief is for the intake valve and yes it's on the right.