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Message: [QUOTE="BrewTown, post: 1567211, member: 31811"] I'll have to look for that 6.7 vid. Did SOA put it out? Or was it someone else? That 6.3 is always an engine I had question about. Seems like a lot of money and work to go through to put a 6.4 crank in. And I don't think it's even for the reason most probably think. 6.0 and 6.4 have the same stroke, so they must be offset grinding the 6.4 crank (larger rod journals) to get a little more stroke. Now physics says more displacement makes more torque and moves the RPM band down, because an engine is just an air pump. But you are spot on that it's really misleading pitting stock vs. slight stroker and hot tune. I'm not sure if I agree with if it made a difference in emissions or noise the OEMs would do it. That would require 2 things, little to zero cost increase, zero time increase. If they could reliably and consistently cast them, and there wasn't extra machining, I could see it. Ford was famous 40 years ago for making the wiring harnesses barely long enough to save cents on each harness. Bottom line it saved a shit ton of cash. If you read up on SOA website, I believe they claim this tech has been around for a very long time. Which I believe it has, race teams have been experimenting with dimples in intakes and heads for decades, with slight improvement. They claim no one could get the piston design correct where it made a difference. Now with the expensive modeling and FEA software available, there's tools to see what's going on. Your top fuel comment got me thinking, I wonder if the dimples on the pistons have a diminishing effect as RPM increases. That concept makes sense to me, as there's less time for the fuel to fall from suspension and stick to any of the surfaces. The air is moving so fast in those top fuel engines at that high RPM, and they have soooooo much fuel! I think the principal this is supposed to work by may be in question. Think of the dimples as breaking surface tension. That's why golf balls can fly as far as they do, and MythBusters has a show on it with wind resistance/fuel economy of a car. In cylinder the fuel falls from suspension and sticks to every surface, piston, cylinder walls, everything not too hot to start combustion. The more volatile the air is, meaning the air touching the piston surface, the more it moves that fuel from the surface. You may be amazed at how wet an intake manifold and runner are on a carbureted engine while at low rpm. I don't want you to take this as I'm attacking anyone, but I don't think the spark plug in top fuel theory holds water. Spark plug design is for longevity. Copper works great, for a while. Platinum, Iridium, unobtainium last longer between changes, not necessarily make any more power when fresh. Good discussion here. [/QUOTE]