Yeah, I put down 66 hp on a crank dyno with a ported 350, that is gonna be one of the most accurate dynos out there. If your using a factory dyno that's that far off, then how do you know the actual correction factors are making the graph curves turn out right? Most "Factory" Dyno numbers I have seen are exagerated and not under shot by any means. I wouldn't be worried about the end numbers, but if it is that far off, then how do you know its using the right formulas to gain accurate results for readings. Dyno jets are not accurate by any means, but even the 70hp mark seems way off.