Well its about time everything comes in so much better on the site, props to the moves on the DNS.

Now for the question, I have searched and searched and used that button with the letters e s a h c r d (with another "e") and I cannot find out for the life of me the mystery of all questions. On the flywheel for a T-5, to use it behind a 1996 350 roller block one piece rear main seal, is it internally or externally balanced? I know the 400 is externally only, but some posts on here are confusing me that some say it IS cause of the counterweights on the flywheel, and is it neutral balanced? The motor is not balanced in any fashion, it doesnt have barely anything for miles and there is no need to beef up the bottom end, not pushing over 500+ HP so its easy to say its stock. If you could quell the confusion I will stop punishing myself and move on to the next dumbest thing...

 

all SBCs are internally balanced except the 400. the flywheel/flex plates for the one piece seals have a bat wing weight to replicate the mass of the flywheel flange on the crank that is no longer there. lot of people get confussed about this as does some parts suppliers. the determining factor in balance is the mass of the weights on the crank compared to the mass of the rod/pistol assembly, not the bat wing weight on the flex plate. you do need to match the parts to your application.

 

WRONG QUESTION.

The 350 is internally balanced, same as a 305; the 1-piece rear main seal motors are internally balanced, same as the 2-piece ones, the last little bit of the internal weight is just located on the flywheel instead of on the crank flange. So everybody that doesn't know what "external balance" really means, will look at that weight that's "external" to the rear main seal, and think that it's "externally" balanced. But it's not. It's "internally" balanced, even though part of the weight is plainly "external" to the motor. And that's the source of the confusion.

So DON'T ask that question! All you'll get is a bunch of confusion and conflicting misinformation.

All you need is the correct flywheel for the transmission setup you're using it with. The correct flywheel is not specfied in terms of "internal" or "external". The correct one will be a 86-92 305 one if it's a T-5, or a 93-97 LT1 one if it's a T-56. Don't even bother with the "internal" or "external" business; just sidestep all that and get the right flywheel and be done with it.