Kennedy adapter question......

If you've installed a Kennedy adapter in anything then you're well aware their instructions leave a lot to be desired. I've seen assembly instructions for Chinese made lawn furniture from Walmart that read like Shakespear in comparison.

Here'a my question..... The backside of the Kennedy flywheel has a deep machined inset. What is that for? Seems like an awful lot of metal if just for balancing purposes. Is there some other reason? Place to store your golf clubs?

Related, there doesn't seem to be a key way, or some other locating feature. Matter in what orientation this is bolted to the crank?

Any help is appreciated.


I'll assume you have a 5.0 302 SBF Cliff, that looks like a 50oz external balance to me. There is one flywheel bolt hole offset that ensures the flywheel is correctly indexed to crank, so dont go doing any 'Cliff' mods like offsetting the other holes to make it fit or you will find you have built a vibrator into your car which might not be your end goal!

Terry Oxandale

Skinny Man
Wow! that's some balancing act there. The Ford (for example) has the crank bolt holes unevenly spaced so that there is only one way the flywheel can be bolted onto the end of the crank, so you may have to place it on the crank and rotate it around until all six holes line up (and it won't be much of a mismatch, so look carefully).

Howard Jones

My advice is to have the rotating assembly rebalanced with the flywheel and flywheel dampener you select. Sometimes the balancing shop will also want the clutch pressure plate, mine did....more than once.

I know it/they say that the flywheel is pre-balanced to the appropriate balance factor, 50 or 28oz in the case of a SBF. The dampener should be also......BUT when it all goes together the minor individually "within spec" variances all stack up and they can reach a value of imbalance that creates Jac's "vibrator" scenario.

This isn't theory, it happens.

A couple of articles on balancing.

Maintaining Your Balance: Engine Building Tips to Reduce NVH and Increase Life - Engine Builder Magazine

Balancing Equipment: a weighty matter - Engine Builder Magazine

Engine Balancing | Grumpys Performance Garage
Thank you fellas, this is very helpful.

Good advice with the re-balance idea. Just to be clear that means taking the front balancer, crank, and flywheel to a good machine shop where they balance the whole unit together?
Yes , plus they need piston/rod assys to weigh in order to configure bob weights to clamp on each rod journal to do the job.