Forged Nitrided, 81.33mm stroke, cross drilled, 1.625" "S" big end journal for 1275 S block with extra strong key for timing wheel fitted.
Forged-YES forged- EN40B steel nitrided cranks are considered the ultimate in specification, even over the "billet" type. This is mainly because the grain pattern of a forging follows the shape of the webs and bearings whereas the billet type is machined across the grain. Heated for maximum durability, these are machined to fit mains width of the Cooper S block only.
All cranks have been re drawn to benefit from latest technology by having the larger crank webs designed to reduce whip and resistance at high revs giving smoother running and easier balancing, plus being mass centre balanced.
The bored holes for the big ends reduces weight of the crank and does not require drilling through the largecounterr balance C shape webs