[chiphead]

That's a pretty mild spring. Did they measure the seat pressure at the 1.675 IH? That's the real question.

How did they get the extra .075? Did they use offset locks, grind the seats, use offset retainers, or did the .075 come naturally due to stacked tolerances? Did they have to use offset parts to clear a Viton seal or something? From my recent install of a 2802, I found that it's tough to get a Viton to fit without machinging the guide down or using offset retainers or locks.

It matters, because if they used offset locks or retainers, you've got to check that the rocker arm you use doesn't hit the retainer. The valvestem stick-out is reduced, so the rocker arm gets closer to the retainer.

But on to the springs. The comp site says those should give 117lbs at 1.6. I did some math and figured about 23lbs of pressure for every .100" inch of travel. So that extra .075" reduces seat pressure by about 17lbs. So you're at about 100lbs on the seat, assuming the printed specs. Now if the guy measured it at 110lbs at 1.675", that could be accurate and due to the retainer used, which will move the numbers around.

Now you could use this to your advantage. With 100-110lbs on the seat you could likely break the cam in without removing the inners. Then once the cam is broken in and has a few miles, you could shim the springs back to 1.6" to get some pressure back.