Re: Roller Rockers in Stock
 

Speaking for the few AMC racers out there, all applications use a stamped steel rocker arm over a ball / stud assembly with no guide plates (prior to last week). Looks just like a SBC arrangement but the rocker folcrum cenerline to tip is about .200" longer and offer's a 1.55 ratio (my testing found 1.53 typical). AMC uses a 5/16" pushrod and a 3/8" screw-in stud. Upgrades can be made to a 3/8" pushrod and a 7/16" rocker stud from a BBC. Bracket racers typically use a modified Pontiac guide plate if neccessary.

As stated by SSDiv6 ..."Chevy and Pontiac have a great selection of rocker arm options"
Yes, especially Pontiacs. I suspect a Pontiac racer or two might not like everybody else having roller rockers because that opens up the door to everybody having the same ratio's available. I'm not personally aware of any conclusive evidence that shows a 1.65 rocker ratio has a decided advantage over a 1.5 rocker ratio (both theroretical ratio's) in a Stocker application (both offering the same gross valve lift) but I would suspect there is some advantage although miniscule. Personally, I always built a cam around the rocker ratio.

Re: Roller Rockers in Stock
 

Ed is correct...Buicks get the short end of the stick in regards to rocker arms.

Re: Roller Rockers in Stock
 

As stated by SSDiv6 ..."Chevy and Pontiac have a great selection of rocker arm options"
What are they? Are they good? What about adjustable pushrods? Did they come from the factory?

Re: Roller Rockers in Stock
 

Steve, the aftermarket has lots of offerings for both makes with better materials and treatments. The adjustable pushrods did not come from the factory and were allowed by NHRA many moons ago, to give an option to other makes of engines that did not have adjustable valve train. My own preference, although more expensive, I would rather have custom made pushrods in lieu of running an adjustable push rod due to its weight.

The funny and interesting part of this discussion is that many of you are bringing up issues that have been in the rule book for over 20 years such as adjustable pushrods and the ductile iron rocker arms in Mopars and at the time, no one made an issue of it until now. Do not get me wrong, I recognize many of you have devoted most of your life to a few makes of engine manufacturers and are not knowledgeable on other makes.

Re: Roller Rockers in Stock
 

Steve, the aftermarket has lots of offerings for both makes with better materials and treatments.

I have tried them all at great expense. The bottom line is that they are still stamped steel and not made to do what we are asking. As many have stated roller rockers are not a performance advantage. Don't you think the adjustable pushrod is a performace advantage that was allowed? Adjustable rockers on cars that they never came on? ETC.

The funny and interesting part of this discussion is that many of you are bringing up issues that have been in the rule book for over 20 years such as adjustable pushrods and the ductile iron rocker arms in Mopars and at the time, no one made an issue of it until now. Do not get me wrong, I recognize many of you have devoted most of your life to a few makes of engine manufacturers and are not knowledgeable on other makes.

SSDiv6: This is just the point i'm trying to make. Thing are allowed when there is a problem. Stamped steel rockers are a big problem.

Re: Roller Rockers in Stock
 

Steve, I agree, stamped steel rocker arms are the big problem. You do not have an idea how much research, test and analysis I have done on the current stamped rocker arms. My conclusion is the inconsistency in metal thickness and low grade materials and poor quality.

Re: Roller Rockers in Stock
 

Well SSDiv6, you may have access to scientific instruments and labs, but I knew from the get-go :confused: when I took a Speed-Pro/TRW AMC rocker and "thunked" it with my fingernail and it went "dunk" :mad: and the OEM rocker went "diiiinggg" :), then surely the factory offering was better :eek:. Although that did lead to a rockwell hardness test which confirmed a huge difference as I suspected...

Re: Roller Rockers in Stock
 

The lab test allowed me to see the variation on materials and try to find the solution. Yes, you can do it the "Redneck" way via the resonance test, however, I was trying to find how much variation between manufacturers, its ductility and malleability. What I also found with the replacement stamped rocker arms is that in addition to the cycles and loading they are exposed to, the heat affects the malleability.

Re: Roller Rockers in Stock
 

As I see it from the technical stand point the stamped steel rockers are inferior to the ductile iron rocker arm. Then why would the Chrysler and Ford guys running the iron instead of the stamped steel (ORIGINAL) rockers want it for the Chevy guys WHEN THEY HAVE THAT ADVANTAGE? We have no option!

Re: Roller Rockers in Stock
 

Steve, in addition to Mopar and Ford, there are Chevy, Olds, Buick and other makes, asking for the change.