Originally Posted by spinn
Installed at 1.8 they were about 95lb seat and open 275 at .500
Installed at 1.6 it was 125 and 305
This would be a 360 lb/in rate.
This is very close to the Comp Cams spring p/n 26981. Seat 110# @1.7", open 292# @ 1.175 (0.525").
My question is why would GM this spring on the 3100? Maybe it's because of the redline of this engine. Or a tall installed height... Anyone know what the installed height is on the 3100? Or the redline?
I know the redline of the '09 Impala 3.5L is 6400 and will rev higher.