I have a boosted 340 built in the late 80s. I can tell you what I learned about boost and timing. Pistons are expensive. That being said boosted motors don't run anywhere near the same advance as N/A. Once I got the timing under control, same pistons since 1991. E 85 is definitely better. As far as blow thru E85 carb Dizuster uses Eric at Horsepower Innovations. It has been very good.
Doug