5.3 on 4.3 4l60e
http://www.summitracing.com/parts/HUP-HP3795/
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Durability??? 4L60 trannys have run behind millions of Chev/GMC truck 5.3L V8engines for years and are still available on 2013 Chevy models.
IMHO, unless you are going big HP or dragging you will be fine.
The Best V8 Stories One Small Block at Time

FYI - We're talking 1997+ six bolt tail housing 4L60E's which is the only version of that transmission I work with. Earlier years may be different.
The V6 / Gen I/II transmission has a different bell housing, input shaft, input shaft depth and converter compared to the Gen III (LSx) V8 variant.
The two easiest ways I use spot a V6 / Gen I/II vs. Gen III (LSx) V8 transmission are the bell housing and the input shaft.
The V6 transmission does NOT have a top bolt and the bottom bolts are different:

Our V8 counterpart DOES have the top bolt:

I haven't counted splines, so I'm not sure about the count (looks the same). I did measure them and the input shaft diameter is the same size (slightly off due to trying to measure inside the bell housing while taking pictures at the proper angle to read the LCD), however the design differs between the two. I would assume this means torque converters are not interchangeable and looking inside them I believe this is accurate.
V6 input shaft has the small nipple on it:

Our V8 friend is splined all the way down:

What this means is the V6 transmission will work with a Gen III engine WITH a spacer and a dished flexplate. It also means it will work with a flat flexplate AND a spacer. Either way you need the spacer or a special (usually SFI approved and expensive) flexplate.
Dished flexplate: Crank, flexplate, SPACER.
Flat (6.0) flexplate: Crank, SPACER, flexplate.
The V6 transmission will need to have the torque converter holes elongated to work with either flexplate.
Obviously the Gen III transmission doesn't require this drama because it's designed for the engine it backs.
Hope this helps.







