[bxd]

Yes, the insulators from Turbo Kraft are made from the same phenolic material that the PMO blocks are; the guys at TK would be able to give you more detail on this than I can.

If I can offer my two cents on the stepping issue; I've discussed this on several occasions with my mechanic and this is what I've come to understand: -These small steps or variances between the carbs and the heads won't really be noticeable on a dyno. However, by smoothing out the flow, you may (as in maybe or maybe not) notice a slight difference in low-end torque vs. top-end speed (in my case I'd probably lose a minute bit of low-end grunt but gain a very slight bit of top-end speed). But for this to really be something you feel in your foot, the carbs must be in perfect working order, must be tuned correctly, with no air leaks or blockages, and all the gaskets must be air-tight. -And on the street, a slight bump in top-end speed is not really going to be usable anyway, right?

I guess the message here is that this is a system, with air/fuel mixture being of primary concern, and if the carbs aren't in good shape and setup correctly etc., then laminar flow or atomized fuel suspension, or even slight compression/expansion inside the manifold/port is probably not the primary issue. For my money, and since my car runs fairly well as-is, I decided not to get all tweaked over it and opted to address the stepping when I rebuild the carbs sometime in the future.