Just get the B&M flexplate for the externally balanced 440 and be done with it. Then you're free to use whatever converter you want. Not to mention it's just a simple bolt in deal and easier than trying to find someone to weld on the weight in the correct spot on the converter.
B&M 10238 if you have a forged crank ext. balance 440
B&M 10237 if you have a cast crank ext. balance 440
CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax
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