Interesting pics, Paul. Just goes to demonstrate why our airplanes are "Experimental".

As in the current thread on methods of fuel management in LNC2's, there are as many ideas (good, not-so-good and in between) as there are airplanes and builders.

I also semi-wrapped my cylinders with Al shrouds, with an outlet around 1 inch across - though I didn't go to the extent that you did, with the outlet ducting seen in your pics. I'm sure I could squeeze a few more knots out of N235SP if I did but, for me, it's not worth the time and effort. Even without the exit ducting as in your airplane, I have a problem (most of the time, in cruise) getting the CHT's high enough to where I think they should be - I rarely see higher than 300 - 320 dF. Not ideal, but probably better than running too high. The higher CHT's are probably more important in the larger engines to keep from wiping out the choke (I have a Lyc O-235-L2C in mine).

Anyway, you have an interesting LNC2 (LNC2.5?).

Dan Schaefer
N235SP    Early 235.