Chev 350 flywhelel

So far I've gathered this...
'85 down = internaly balanced (0 ounce)
'86 up = externaly balanced (whats the imbalance??)

And do the 4.3's share the same flywheels at the 350's?? (imbalances, ect.)
Noticed there are two sizes for Crankshaft bolt pattern, so far I'm 'ass'-uming that signifies internal / external balance??
6 on 3" and 6 on 3 5/8" (rough measure with a tape)

the quickest way to tell is the one peice crank seal. the old style wheels don't bolt up. and the 4.3 was two peice in `85 so there is two different ones. the tooth count is different from engine to engine. so you have to go by application.

Heres my gig....
Replacing the bunk engine in my boat (4.3L) {boat is an '86}
Have a new engie all rebuilt and sexied up.....
Found out the old 4.3L has a crank BP of 6 on 3 5/8" and the new engine has a crank BP of 6 on 3", AKA... not a good morning.

Wondering what kinda vehicle apps I can score a flywheel off of.
Nobody seems to know if 262 and 350 flywheels are swappable.
And since they are externaly balanced... what is the imbalance? (??ounces)168 tooth ring gear / 29 pounder / 13.25" across flywheel(not ring)

http://www.bloodydecks.com/forums/index.php?

if its boating question why didn't you say so!