Ventilated Cross over Block

[Deer Slayer]

Update; First tank of gas the F6B with the vent block had better fuel mileage by approx 1 mpg. We shall check more. However at this time the vent Crossover Block does not seam to hurt any performance. We shall keep checking. :039:

[srt8-in-largo]

What is this crossover block?

I'm always for better mpg's with no power loss.