Re: IO-375 Install
I'm still working on the cowl and baffles, but haven't run into any issues and don't think I will. Externally, the IO-375 is dimensionally equivalent to the Lycoming parallel valve IO-360, so all of the components that work that that will bolt right on to the IO-375.
There are a couple of things to be aware of though. The ECI cylinders have tapered fins which will require modifying the baffles. Also, Bart at Aerosport recommended installing the Stewart Warner 10599R instead of the more common 8432R because of the additional heat generated by the larger engine. This is a bit of a pain since the 10599R is over 1" wider than the 8432R. This makes it challenging to mount on the baffles and the extra weight will likely require even more baffle reinforcement to avoid cracking. I'm still toying with the idea of mounting the oil cooler to the firewall as an alternative.
Larry Vetterman recommended the four pipe exhaust for the IO-375 which is what I installed. Not only does this look really cool with the four pipes coming out of the cowl, it allows the heat muff to surround two pipes instead of one which provides significantly more heat for the cabin. The lack of cross over pipes also appears to reduce the interference with other components in the cowl.