[kobrabob]

SFfiredog and Michael Henry are right in that 428 are externally balanced and al other Ford Fe engines are internally balanced.

Use 428 flywheel on a 428 crank and if you do remember the dampners are different.

I too, have interchanged many an FE and not run into trouble but never played around with 428 flywheel on 390 or 427.

You can bolt on a 352 or 390 any externals and most heads but beware of 427 heads, I remember hearing something about valves hitting the block.

bob