Hi guys,

I bought a 440 that was running a 509 cam and I am switching it to a XE274 comp cam. The springs in the heads are Comp PN 924-16 duals. Comp calls for a single spring, PN 911-16. A few questions:

Am I pushing my luck running the dual spring? Obviously I would break in with inners removed.

Should I replace with single spring, and will the fact that the heads were machined for dual springs cause any problems?

Thanks!
Paul

What will the pressures be at the new installed and open hieghts?

the 924 spring is gentler than than the 911. the 924 has a lower spring rate but i think it's up to the task. the 924 is recommended for the 275 hi-lift and it's more aggressive than the 274. the 911 is a pretty aggressive single spring. if it were me i'd use the 924 for reliability vs the 911.

924 comp spring is a good spring for that cam.
125 on the seat with 315 open, @ 1.880 installed. your heads are possibly closer to 1.860 installed height so you should still be ok. No need to remove inner spring, use a good 30 weight brad penn break in oil and a good wix or napa gold oil filter and keep rpm up on start up.

MLR426