This morning'* pics:
And a comparison between the ZM stage 1 LIM from last year (left) and the ZM stage 2 LIM for this year (right):
Stock (OEM) ports are roughly .8x1.8" (1.44" square)
Stage 1 ports are .9x1.9" to match stock heads (1.71" square)
Stage 2 ports are .95x1.95" to match newly ported heads (1.85" square)
OEM to Stage 1 (matched to stock heads) is an 18.8%
increase. (what I ran last year)
Stage 1 to Stage 2 (matched to ported heads) is a 8.2%
increase. (last year to this year)
OEM stock ports to stage 2 is a 28.5%
increase over stock.
You can see it doesn't take much to gain in flow, even when simply matching stock head ports. The L36 has a larger gain due to the poor LIM castings, but the S1 L67 still has a bit to gain, which is very beneficial as the S1 L67 runs out of breath at the upper RPM'*.