Drilling flywheel for 360 balance
 

Back in 2014 when I bought my 360-engined B350 I had a flywheel drilled to suit the external balance characteristic of this engine...

This was arranged by a friend of mine in Spokane WA, and when we fitted it up I was surprised at the way it was drilled. Unlike the regular (and readily found) pattern of three 1 13/64 holes on a 3.88" radius from the centre, it had five holes each of 0.75" diameter and approximately 0.6" to the bottom of the centre of the holes. They are drilled about 5.4" from the centre of the flywheel.

When I queried this I was told that this was a regular alternative drilling used on larger flywheels.

Now, as I ponder all the variables while fitting an NV4500 to the van, I find I have to use a larger flywheel and, of course, I have to balance it to suit.

If the method used in Spokane is a regular alternative, I'd imagine I'd find mention of it somewhere or other. Has anyone ever heard of it?

The reason I ask, of course, is that I don't have that 1 13/64 drill but I can get a 0.75" drill easily enough.

Other than drilling the flywheel, there is the option of putting one of the Quick Time plates on there, but it sort of goes against the grain with me. It distances the flywheel from the crank by whatever thickness it is and I don't feel that's sound engineering.

A bolt-on weight would be more attractive, I feel, but I don't see anything like that anywhere.

Anyway, asking the questions might get answers...

Is the drilling method used by the people in Spokane a Mopar method? Or a good alternative that's documented somewhere?

Is there a bolt-on weight I can use as an alternative?

All assistance greatly appreciated...

I forgot to add...

Here's a picture of the flywheel as drilled in Spokane:

https://i.postimg.cc/K8Cw2cQj/0323ol...eldrilling.jpg

I must add, it seemed to work perfectly.