Anybody know if there is any significant horsepower to be had on a hi-po street/strip motor from one the hi-tech harmonic crank dampeners vs. the factory piece? I am running a fairly healthy 360 SB (317 rwhp) in a '70 Dart.

Thanks in advance for any input.

no horsepower, safety and possibly longer engine life, but no extra horsepower.

High tech dampeners claim to neutralize harmonics over a wider frequency than elastomer dampers which are designed to handle a very narrow harmonic, usually in the cruise rpm range. SFI dampners are rated to a higher RPM, silicon dampeners are usually lighter by about 30%, and the mechanical "Rattler" type dampers, I got no clue.

Dampners do not make horsepower. They do allow the engien to not use as much power during running. So a good one can add wheel hp, if the one you've got now is that bad. All dampners as stated are only good over a certain frequency range, and I can't tell you what that is specifically. I'd ask ATI about it... IN terms of materials, they all do the same job, just in different ways. Personlly, I see a lot of talk about expense of internal balancing and blue printing in the machining stage. Good parts, perfectly machined and balanced will go a lot further to making power than a $600 dampner will. But keeping the blocks in good shape, allowing the parts to handle more power for a longer life sapan, that's where the dampner comes in. I personaly stay away from any fluid ones. I dont like leaks, and I ahvent seen a single one that over time doesnt leak a little. SFI simply means they have been spin tested to above 12,000 rpm IIRC. It has nothing to do with harmonic ranges.

Thanks to everyone for the info. Sounds like hi-rpm safety and reduced wear would be the primary potential gains. I do worry a bit that the factory piece is not SFI certified even though I only spin it to about 6200 rpm.

Anyone else aware of leakage problems with the fluid dampeners? Lighter does sound better, if it will still control all the vibrations as well as the heavier piece.