Questions about using a Lycoming 0-320 and the Panther LS model are posted on the PantherCave (forum). Here is a direct link to the topic:
Here is SPA's official stance on the Lycoming 0-320 and the Panther LS wing option:
The Panther LS (sport pilot, LSA, long wing ) is not approved by SPA LLC for 0-320 engines or engines in this class.
Due to the Panthers exceptional performance, we are continually questioned about LSA compliance. LSA compliance is plausible and documentable with 130 hp. See HERE for the LSA requirements and how the Panther LS meets them. The Panther LS is designed for 80-130 hp and about 250 lbs engines. The Panther Sport (short wing) can be set up for engine from 80 -160 hp and up to about 320 lbs total INSTALLED firewall forward weight.
The Panther Sport was designed to accept the very lightest 0-320s, the narrow deck conical mounted early 0-320s and a light wood prop. The first "sport" builder, Bob Woolley, found a good deal on a wide deck dynafocal #1 (30 degree) engine and decided to use it. This engine and mount will weigh almost 20 lbs more than a early conical mount narrow deck. SPA is building his mount but he understands the useful load will be limited.
The big misconception is the "dyna 1" engines will be "smoother". This is true only if running a heavy metal,or constant speed propeller, neither of which are approved for the Panther. The conical mount and dyna mounts are equally smooth with light wood props. (The lust for dyna mounts is rooted in the Vans RV world where the dyna mount means it is likely a newer vintage engine, and many are using metal and constant speed props)
The "universal" cowl fits ANY 0-320, 0-290, 0-235, 0-233, 0-200, UL 350 etc. We highly recommend conical mounts!!! We will sell Dyna #1 mounts but it will be noted "not approved for dyna #1 0-320" on invoice. The 0-233 with dyna 1 is fine.
If you are looking for an 0-320 for a Panther Sport (short wing) an older conical narrow deck 0-320 will be an excellent value.