Anybody know the deal with flexplates?

I'm trying to figure out which parts I'll need for each scenario.

Scenario 1

'04 LS1 with '04 LS1 flexplate to a 4L60E from 99-06 Silverado and converter from a 99-06 Silverado

flexplate should bolt up on that one I think, no big deal.

Scenario 2

'04 LS1 with ??? flexplate, bolts, spacer ??? with 4L60E from the 98 Tahoe and converter from 98 Tahoe

not sure, I think I need a new flex and spacer with different bolts on this one



I called S&P in Arizona, but evidently Mark (the man who could answer my ?s) won't be back til Tuesday.

Any help is appreciated. Thanks guys