95 Sierra LS swap with a 97 4L60E

[Triprocks]

Okay, everyone has their opinion, and we all know what an ******* smells like. That being said, I'm needing facts, not opinions. The spacer for the 97 4L60E, is there anything else I'm gonna need to marry up the 97. 4L.... With a factory 2002 5.3. some say the LQ9 or 2002 6.0 flex plate will correct any fitment issues I will encounter. Others say the 2002 5.3 will bolt up to the 97 4L60E with no problems because the 2002 5.3 flex plate already has the required spacers and torque converter bolts need to be longer and shimmed with washer to fill any gap between the converter and flex plate.
I just want to have all my parts in hand before I start this adventure.

 

[Schurkey]

Perhaps a moderator will move this thread to the LSX + Carb Swaps sub-forum.

 

[Javlin42]

The spacer is only needed to bolt an LT-style 4L60E to an LS engine.
All pre-98' are LT style but some later years from non-LS engines are also LT-style.
LT style have a 298mm input shaft. LT converters have a shorter pilot.
LS style have a 300mm input shaft. LS converters have a longer pilot.
LS style have a slightly deeper bell housing and have a bolt hole in the 12 O'Clock position.

Most LS engines have a shorter crank that LT or SBC/BBC engines; hence the spacer is needed to properly engage the short LT converter's pilot into something solid. Alternatively a pilot extender can be used to engage into the crank.
An exception are some '99-'00 6.0L truck engines have a long crank LS-engine and came with the 4L80E trans. They would not need a spacer, but conversely will not directly bolt to an LS-style 4L60E. If really needed, the converter sponsors can make custom converters to solve incompatibility problems.

 

[Erik the Awful]

According to Summit's exceptionally helpful "Which LS Do I Have" pages, your LQ9 has the thicker .857" flange. You should be able to bolt the transmission directly to the engine without a spacer, but I haven't actually put hands on an LS engine yet, so trust me only as far as any internet whacko who tells you "what you should do is..."

Chevy LQ9 Engine Specs · Help Center