90# and 105# IS THE SEAT PRESSURE RATING.Originally Posted by ADecker
XP cam, 105# valve springs and a stock chain and tensioner is not a recipe for a durable setup. I remember one customer who ran that setup and replaced his tensioner after a couple years of service time, describing it as doing the replacement just in time.
On the flip side, I've had two customers who did double rollers, Rollmaster doubles, who had their chains stretch so much it finally wanted to jump a tooth, chipped the gears and the motor failed. One was after only 3 years of service time but 60k+ miles. By comparison, several motors I was building 8-10 years ago with the JP double roller chainsets, including my own GTP, are still going strong. When Rollmaster bought JP and the quality went to crap, I was disappointed because JP seemed like the right choice.
Anyhow, we can debate springs and chains all day long, I'm still convinced that many builds will have a 3-4 year lifespan. If we were more LS like with our parts availability, we'd do 130-150# springs, a trunion upgrade in our rocker arms, and a strong durable timing chain and non of this would be a debate.
