I cannot speak for the Else cam’s exact technical spec. There were at least two different Else grinds for the S2 as reports from the day vary quite a bit on idle speed and low speed drive-ability. One tested example put out a reported 140 hp but was a disaster in city traffic. Other tests were delighted with the “all-round” improvement.
The 1470 S1 engine was based on the 60-ish hp R16 lump. The lotus engine received larger valves, sportier cam, (much) higher compression pistons, and a two barrel carb and manifold for 84 hp. Reputedly the engine was from an order of marine engines that wasn’t completely sold.
The early S2s kept the same 1470 engine. While some 1470s snuck into the US, they were fortunate to be able to use the federalized Renault 16 1565 and avoid the huge expense of having to certify an engine. The federal 1565 had individual ports, two barrel carb, sportier cam, high compression, and a longer stroke.
I think the S2 cam is not as “sporty” as the S1 cam as the S2 is torquier and doesn’t rev as high. It could, however, be due to the longer stroke, hard to say as the Lotus 1470 is not well documented.
The Else cam requires piston mods due to higher lift. Why the S1 version doesn’t, I can’t say. Different crank strokes have different piston accelerations and, thus, different piston positions off TDC. Perhaps the pistons just aren’t “in the way” on the shorter stroke S1.