About Nodular Iron
Nodular Iron, also referred to as ductile iron, is typically the material used for heavy duty or racing applications of cast iron products. It is approximately 30% stronger than gray iron. So it was only natural that when PRO/RACE developed the heavy duty OE replacement PRO/STREET dampers, high strength nodular iron was the material of choice.
While PRO/STREET dampers are not intended for racing, the fact that they are cast of nodular iron, as opposed to ordinary gray iron, means that they are suitable for higher rpms than most competitive models. (Note: The PRO/STREET Nodular Iron Harmonic Dampers are NOT SFI certified). However to prove the integrity of the PRO/STREET dampers, we had the SFI test lab run some spin tests. The PRO/STREET damper was subjected to 8,000rpm for one hour, and then 12,500rpm for 15 minutes with no sign of degradation! (note: this by no means suggests the PRO/STREET damper should be used in extreme applications – use PRO/RACE or PRO/SPORT for high performance applications).

Bonded elastomer
Unlike many OE dampers, or other replacement style dampers, the PRO/STREET range feature a bonded elastomer! The elastomer is injected at high temperature and under extreme pressure. In fact during the manufacturing process EACH AND EVERY PRO/STREET damper is subjected to elastomer bond test of 3000lbs (2000 lbs on 24262) separation force. If there is any sign of bond degradation then the damper is scrapped. Many OEM dampers aren’t bonded at all

Removable Counterweights
Harmonic dampers are supplied in two styles; those for internally balanced engines and those for externally balanced engines. Externally balanced engines have a counterweight bolted into the hub of the damper. The advantage of having a removable counterweight in the hub eliminates the possibility of having the counterweight mass move from its position plus it provides an extremely accurate external balance mass.
The PRO/STREET Damper for internally and externally balanced small block and big block Chevys and for small block Chryslers is identical except for the counterweight. This means, for example, if you have a PRO/STREET Damper for a 400 small block Chevy you can remove the counterweight and the damper will work perfectly for a 350 Chevy. Conversely, if you have a 350 Damper and want to use it on a 400 you can now purchase the proper PRO/RACE counterweight and bolt it into your 350 damper and it is now a 400 damper.
All Ford dampers are externally balanced with a counterweight. This counterweight can be removed for use on internally balanced engines.

Machined to tolerances exceeding OEM specifications!
The PRO/STREET dampers have been machined to tolerances far exceeding those used by OEM’s. Just take a look at the overall surface finish and oil seal and bore of the damper! Permanent rolled-in timing marks are very visible and will never fade or become less visible!

Brand Name You Can Trust
These dampers are from PRO/RACE Performance, a leading manufacturer of racing SFI-Spec. dampers, so you know they are a high quality, yet affordable, damper for heavy duty street or replacement applications. Note: Externally balanced models are supplied with the necessary counterweights. Counterweights are also sold separately.