This one was done a few years ago. The engine has gone through a number of changes since then, which have added power. The last dyno tune showed 510 peak hp. But I just made some big changes that probably decreased power a bit; but it hasn't been to the dyno yet. In any case I like this one because of the comparison.
The initial test was done with "Tea Strainer" filters on the stacks. Then we popped the air cleaners off and did another run right away. No other changes, just removed the tea strainers. The difference is nearly 100HP! Looking at the AFR curve, I suspect that you could gain some of that power back by leaning out the mixture a bit. But I doubt you'd get 100hp. I doubt you'd even get 50hp. Those filters are really restrictive.
