Comp cams xe268h for 318

Woo-hoo on the cam selling! OK on no computer.

You are using the right ICA number there, so that is good. Some perspective info on DCR:

• Stock earlier LA318's DCR is usually in the high 6's to 7. Ditto for a stock LA360. It got up into the mid 7-ish range when the Magnum's came out. (These number are for sea level.)
• So if you hit 7 or better for DCR, you are getting better than a stock LA318. OP, your prior cam was heading for the low-mid-6's. (Put in an ICA of 67.)
• The higher you go, the better the low RPM torque, throttle response at low RPM, etc.
• When you approach 8, then you start getting close to where an iron headed engine will detonate on pump premium. So that is an upper limit, but you won't get there unless your static CR is in the mid-upper 9's or higher.

So you can see that either of these cams exceed a stock LA318 by a bit. 'A bit' ?!?! LOL... Before you say 'why bother'... remember, this is just for evaluating low-mid RPM torque; the added lift and duration is what will make the mid-high RPM torque and HP much better than stock.

If you want more low RPM uumph, then put in 9 for Static CR and see the DCR number push up towards the mid 7's; that would be for the thinnest head gaskets and milling of your 302 heads down to 60 cc's or less.

Now that you have this tool working, you can also see the effects of changing cam timing. To see the effect of a 4 degree advance in cam timing, subtract the 4 from the ICA you put into the calculator. Example: For the 262, the ICA goes from 57 to 53 with a 4 degree cam advance. This explains/models the old advice to advance the cam for better low RPM torque.

In general, DCR is a tool to let you:

• See how a combination will do for low to mid RPM torque. It does not model all aspects of low RPM operation (like reversion, and cylinder clearing effects related to SCR), but helps in narrowing down your cam for certain applications.
• See how close you are getting to detonation tendencies around the peak torque RPM
• A .1 change is not a big deal for most situations, and, getting beyond that level of accuracy is not realistic anyway. (So I don't get hung up on DCR at that level.)
• However, a half a point difference WILL show up with significant changes in low RPM torque and driveability (throttle response). And even a .2-.25 point change will be felt the first time you press down the throttle.
• Going low-mid 6's tells you the engine will be doggy at low RPM's.
• It is a numerical way to try to be objective in cam and compression selection and has been used since the 60's for hot-rodders. You don't have to blindly follow someone else's formulas or build, or to build and experiment.
• It was/is tough, and beyond the abilities of most hot-rodders, to do by hand. The online tools make it easy to compute and evaluate for anyone interested.
• The value to the engine builder may vary with the application. IMHO, it's highly valuable for applications needing a wide torque band (daily driving, cruising, road race, rally).