Flywheel Internally Balanced Or External

[tayoz2005]

I am trying to build my new motor for my truck and came to this problem when putting the old flywheel from my blown motor. It will not fix this crank. The motor was set for marine standars. Now the question is i have no idea if it is internally balanced or externally? Any ideas on how i could find this out. Also the new motor did not come with a crank

[Cadha13]

Is it a two piece rear main oil seal or a one piece? On Chev SB's after 1986 they were externally balanced one piece and all 90 deg. V6's are one piece externally balanced and the BB's after 1991 are one piece seal. Before are internally balanced two piece rear main seals on SB V8's. There are kits to convert the one piece seal on these 86 and later blocks to use stronger cranks from the two piece engines to make use the two piece seals.

[tayoz2005]

this is a 2 peice main seal. It was originally set up for marine standards another thing i can tell you is that on the crank it looks like it has a counter weight type of thing.

[Cadha13]

Then it is a internally balanced crank.