How much HP from SBM ProComps? Well... 670HP!

Right, so you should be pissed off at the guy running the dyno and the customers who are too stupid to deal with the truth and would rather be lied to. I've seen it done with dyno's and flow benches. Try and explain to someone why their 400 CFM actually only flowed 375 and then you work on them and they flow 360 and yet are quicker. You'll be lucky to get paid.
Well, I kinda am!