Originally Posted by AndyF
Originally Posted by Al_Alguire
Man you "Hemi" guys are touchy arent you. I have BEEN there DONE that with both I am not speculating


That has been fairly consistent with what I've heard since the Pro Stock guys gave up on the Hemi 20+ years ago. The canted valve setup seems to have eventually ended up on top after years of back and forth. Of course the SS AH guys keep pushing the bar higher but I doubt that Pro Stock will ever go back to 426 Hemi engine.

Of course this only applies to the super serious pro classes. Hemi engines still have a ton of appeal to street guys and bracket racers as well as some class cars. Just doesn't seem to be the way to go if someone wants to make max power per cubic inch normally aspirated. I don't know the reason, has something to do with the big chamber I suppose as well as how the heads flow in use. The Hemi heads flow like gang busters on the bench so that isn't the problem. I'm sure there are few engine builders who busted their pick trying to make them run who could explain the problem. I've never tried to run a Hemi in Pro Stock so I'm not the guy to ask.


I think Pro Stock comes down to a cubic inch issue. I don't think the Hemi works well in the 500" setup (anymore). The last two serious efforts were Jeff Wick in the mid-90's, and Bill Dempsey in the late 80's. Reid Whisnant's DLI stuff was based on a KB block with heavily modified D5 heads, which were already 10 years old when Landy was working on that program. The current Sonny Leonard Chemi stuff has some similarity to a Chrysler Hemi as far as the the valve layout and chamber, but the exhaust is slightly canted compared to the intake. The piston is mostly flat. Again, cubic inches...these things are king in the Mountain Motor world.