i've got a 94' lt1 im coupling with a th350. i have no flywheel. do i need a balanced or non-balanced flywheel, or does it matter?

my main concern is that the lt1 is properly balanced. ive herd people use terms like internally and externally balanced lt1's. what does this mean, and how should this effect what type of flywheel i buy. and should i be concerned about the torque converter bolt pattern lining up or is that something GM has made a universal fit.

and no im not just going to buy a t56 or aod4speed as opposed to the th350 i already have which seems to be a popular "fix" to other threads ive researched on the net about lt1/th350 setups.

thanks in advance for any help you guys have got out there, i know it can be tedious finding good information out here so it is very much appreciated.

 

Reason they say this is if its a one piece rear main or 2 piece. One piece when you look at where the flywheel is connected to the crankshaft. It will look like a complete circle. 2 piece looks like a T sorta. basically circle almost but 2 cut outs. On my flywheel when i removed it was external balanced by the flywheel. So i would assume if its one piece you would need the external balanced flywheel. But don't quote on this. Hope this helps. Someone chime in if i am right or not.

 

1 pce seal engines are ext balance at REAR only;neutral at front like any other SBC except 400
1 pce has a weight welded to the flexplate. Only a 1 pce flexplate will bolt to your engine; the earlier 2 pce ones have a diferent crank hub bolt pattern and no weight on them

Some aftermarket flex plates come with both common GM ( 10.75" and 11.50" ) convertor bolt patterns. See
http://www.summitracing.com/parts/BM...8/?image=large

while others one have one
http://www.summitracing.com/parts/PI...0/?image=large

Check your convertor bolt pattern 1st
( measure from bolt to center x 2 ) There was another bolt pattern GM used ( 9.75" ) but I think that was only on P/Glides