Well I'm gonna bring up this old thread because I've been researching cams and just read this whole thread. Now I'm more confused than when I started. On the Harland Sharp website, right under the S70037's, there a note: "Special Notes: Adjustable
* Harland Sharp original series, Dodge 5.2/5.9 Magnum V8, "Adjustable" pedestal mount, roller rockers are not designed to be a replacement for the factory rocker system." Doesn't that mean they would not be the right ones??

*UPDATE*
Nevermind, I figured it out. The one's with an "A" on the end are adjustable. I thought the notes corresponded with the columns directly above them.. sorry.

 

Just to clarify as there seems to be some misunderstanding about rockers, ratios, and what you can and can't use with a cam:

1. A higher ratio rocker arm will increase rate of lift and total lift. It does NOT increase total duration. Total duration is measured from the start of the lobes ramp to the end of the lobe ramp. At zero lift the valve stays closed whether it's a 1.6 rocker arm or a 1.7 rocker arm.

2. cam measurements for magnum cams are based on the 1.6 ratio arm. if a cam advertises .512/.512 lift, you must divide the lift by 1.6, then multiply by 1.7 to find the new lift of .544/.544, and match spring lift and check for Piston to Valve clearances. I have heard on a 5.2L with flat top pistons, stock heads and head gaskets, you can run up to about .540 lift before piston to valve clearance should be checked as it's close to the minimum spec. If I were running anything close to that, I'd be doubly sure to check.

3. Roller rockers reduce friction in the valvetrain which increases power and reduces wear. There are needle bearings in the central pivot point and a roller at the tip of the rocker for the valve push rod. The factory rocker arm has neither.

4. As to whether or not to use adjustable rockers, it depends. This info is straight from Randy Jr. at Harland Sharp:

If the base lobe of the cam (the part of the lobe with zero lift, when the valve is closed) is the exact same height as the stock cam, you can reuse the stock rockers or non adjustable roller rockers with stock length push rods. Randy swore to me this would work so long as the height of the base lobes were exactly the same.

5. If the base lobe is a different height, you have 2 options: custom length push rods, or adjustable rocker arms. They make adjustable length pushrods that are used for measuring length, but you must mock up the engine, take the measurement, and then order the rods. For this reason, most elect to use adjustable rocker arms as these take up the appropriate amount of slack in the valve train.

 

Adjustable rods can be run in the engine too.

Taken from Hughesengines.com:

I wonder if using adjustable push rods in the newer HEMIs would help to eliminate the ever so famous valvetrain "tick"???

 

I want to pull this thread back up because it has a lot of great info, and I really want to make sure I understand it all right, it seems like some of the guys that have posted on this thread really know what they are talking about, and since I ran the roller rockers in my 5.2 but no cam I really dont know the answer to this... I have a 5.9 now, and I want to run a cam with roller rockers, but I do not know what my best combo will be? I read some people think that you must stick with 1.6 instead of 1.7, is this true? I do not want to buy 1.7's then find out that I can not run them with the cam I will buy later?

 

If you're gonna put a cam in later, I wouldn't bother with the rockers. You can have the cam custom ground to give you both lift and duration. Most guys go with the rockers as an easier alternative to replacing the cam. I don't see a benefit to doing both, other than the roller rockers having less drag, but you can replace them with 1.6RR and not have to worry about clearance issues. That's just my opinion, I'm sure someone on here will disagree.