Thanks for the reply Dave. It really surprises me how much heat the intake absorbs for not having any crossover. I have been running the 1/2" wood spacers on my 2x4 and it stopped fuel perc in the AFB's. I remember, through the years, seeing many articles about lowering the divider wall on big inch, dual planes to increase power up top. As I recall, it had the effect of making a larger plenum and equalizing access to both sides. I would think an open spacer would basically do the same, but figured that I would ask! Lee.