Externally balanced 428

[mrtleavitt]

So a 428 is externally balanced which means it needs a specific flywheel, unlike the rest of the FE engines like the 390 and 360. My 428 is at the machine shop and they called me today and said they are ready for the flywheel and harmonic balancer so they can balance the whole engine. There is one guy there that has built a good number of performance FE engines including 428s and 390s. I asked since they were going to balance my stock crank if I would be fine using a manual flywheel off a 390 and he said I would need to use the 428 flywheel.
I thought a machine shop could balance the crank so that you would not need the counter weighted flywheel. Is that not correct? Can you not use a neutral flywheel on a balanced 428?

[bmerkley58]

It may be possible to balance this engine internally by drilling holes in the counter-weights and installing heavy metal plugs. The down side is the expense since heavy metal is so expensive. About 25 years ago I had a 427 Ford stroker motor balanced and it cost over $250.00 dollars for the balance job. The guy that did the work said if he didn't have to add all the heavy metal the job would have cost $50.00.

Bob

[mrtleavitt]

A 427 should be internally balanced I thought. To my understanding the 428 was the only FE that had to be externally balanced due to having the longest stroke and such a huge bore. I found out that yes you can balance a 428 internally but it's a heck of a lot easier and in most cases more efficient to use a counter-weighted flywheel so that's what I'm going to do. Found one at Autozone for $70! Thanks for the input bmerkley58.

[Fordnatic]

When I built my 410 (which uses a 428 crank) I had them balance a regular 390 flywheel by drilling (removing some material) to make it balance without mallory metal in the crank. So you don't absolutely have to have a 428 flywheel.

[mrtleavitt]

Thanks, I've heard of the mallory balance and wasn't quite sure what that was.

[bmerkley58]

The stroker 427 I was talking about had a 4.25 stroke crank in it. That is why it was dificult to internally balance.

Bob

[mrtleavitt]

Got ya, thanks. After I posted I figured you had some kind of stroker crank in there plus your post said 427 stroker.