Can you use 918 springs with these 1.80 roller rockers, or would that be pushing it?

Thanks.

 

Not with your cam in my opinion. Seat pressure is OK, but open pressure due to spring rate probably won't get you to 6K RPM is my guess. If you go to different springs, careful of the spring load back to the lifters. The 1.7's might work with the 918's, but depends on how many RPM you want to turn.

 

Thanks, I was thinking that the 1.7s would work for sure. What springs would work with the 1.80s? I have a 6600 rpm redline.

 

Anyone know if I'd make gains with the 1.7s and 918 springs?

Also, if I went with the 1.8s, what springs would I need?

 

I think the 1.7's might get you about 10-12 HP. On the 1.8's, you would be at .596 lift with an already aggressive lobe. The following is my personal opinion: With the 1.8's, you would need something like the Crane 832's or the Patriots and probably some shimming (0.060"). You would be right at the deviding line of lifter issues with the stock lifters, as the open loads would be pretty high. I am not sure I would take the chance if I were in your shoes.

I am running the 1.8's, but my lift is a little lower as well and I don't run up to the RPM you are trying to get to.

 

I appreciate the help! I wasn't aware of all the issues. I'm definitely thinking 1.7s now.

I decided that I'll throw an underdrive pulley on, and I was wondering what other bolt-on could net me a few extra ponies. I'm planning on a 9" rear for next spring, so I was looking for some easy mods for some extra power. I'm at the point where I'd need a pretty big investment to make more serious power. These Crane rockers are not exactly bang-for-the-buck, but I think it will be a nice upgrade for my valvetrain. I think I'm going to pass on heads, nitrous and blown induction.

Thanks again for setting me on the right path!