RE: Ls or ss?
Are you asking what the differences are between the SS and LS engines? just curious or what? any time you want to know specifics about a Nelson engine, you can email Dave Shadel at Performance Specalties.
The long stroke has:
smaller bore, this smaller diameter piston
longer stroke ( big guess, but I think the stoke is .790 )
taller case to accomodate longer stroke (I think the case is .080 taller?)
new carb
new back plate
new head design (both inside cut, and head fins)
Hope that helps. ??
RB