Stock rockers are supposed to be 1.5:1 ratio...but in reality work out to 1.42-1.44 on average.Originally Posted by MurphysLaw88GT
The stock rockers actually work quite well on older designed cams like the mopar performance ones, most of the magnum cams by comp cams, etc....but start getting into the newer "high velocity" or aggressive ramp cams such as the comp XE series, or hughes, the larger cams may present problems as a push-rod is likely to push through the stock stamped rockers. Upgrading them to tougher ones is a cinch, and is inexpensive (like 30 bucks for 16 new ones) with thicker stampings...but the ratio remains poor.
Crane, comp, et al all have nice upgrades...normally 1.5's yeild a nice power increase themselves. Some have trouble going to 1.6's just because they are lazy and don't want to correctly measure the needed push-rod length to keep the geometry correct and just adjust to suit using the adjustable rockers themselves...either way, it's a win, just make sure you take the time to measure everything correctly.
That's another mopar advantage...the lifter base radius is a large advantage for mopars. With larger lifter bases than either ford or chevy, you can get a more aggressive "ramp" with regards to the camshaft...IE, for a given duration, you can have more lift dialed into the cam, without the edge of the lifter digging into the cam itself. Comp XE even has a special sub-sub line (since the XE is a sub-line of cams itself) that feature patterns taking full advantage of the mopar liftter....other cams include Hughes Engines, and Racer Brown cams. If you go to roller cams, the advantage becomes effectively nill.
If you are going to swap to a roller rocker set-up, I'd strongly recommend going with a mechanical flat-tappet cam from either hughes or racer brown. It'll give you a ton of power, ability to rev, great sound, and still be quite driveable vs a comperable hyd cam of the same size, and make more power than the hyd cam too.
And yes...shaft mounted RULES. VERY EASY to work with...