Can I use a pre-1997 4L60E behind an LS engine, and what do I need?

Here's what Jeff Smith explains about the two 4L60E styles:

• Early (1993–99) 4L60Es were designed to bolt to a small-block Chevy. Small- and big-block Chevys place the crank flange about 0.400 in farther rearward than an LS, where the flange is roughly flush with the bellhousing face.
• LS-style 4L60Es have no bellhousing bolt hole at about the 2 o'clock position (viewed from behind), where a small-block bolt would go. That's a quick way to tell them apart.
• The early 4L60E bolts to the LS bellhousing flange with that one bolt position unused. It uses the same wiring connectors, and Jeff believes the same case length and output spline.
• Jeff uses exactly this combination behind the long-crank 1999–2000 6.0, whose extended flange puts the converter where a small-block-style transmission expects it. It uses the stock flat 1999 6.0 flexplate and a converter whose bolt pattern matches the flexplate.

Behind a standard (short-flange) LS, the 0.400 in difference means the converter position won't match without a solution for spacing. Our sources don't give a specific kit for that combination, so confirm converter engagement with the transmission or converter maker. Speedway's flexplate guide covers the standard adapters for older transmissions behind an LS.