I'm about to throw a set of ported heads and an F1 in my '98 Z. I know most people are running 918's with it which are supposed to be good to .600 lift ( someone correct me if I'm wrong ). My question is, since this cam is on the ragged edge of .600 (.591 int. lift) Are the 918's going to hold up to this much lift over time. Is there any other spring, like the Dual Revs, that may be a better choice so I wont have to worry about breaking anything. The the machine shop is gonna assemble the heads after they are ported, so if I went with a spring that requires mods to the head itself, it wouldnt really matter, I just dont want to have to pull it back apart after I get this all done.

Any feedback appreciated!

Thanks

 

I ran 918's for at least 5000 miles with my F1. No probs, but if you are having the heads done, you may as well upgrade to dual springs.

 

I run 918's and will be changing them for new 918's in november -- that's 1 year (approx 9k miles) since they were installed.

I don't trust the rev dual spring and I am waiting for comp's dual spring that fits in stock ls1 spring seat to come out next year.

 

I'm running REV duals - no problem - avoided 918s since they have little quality control.... lots here like them, however...