Rocker Arms
Rocker Arms im thinking of upgrading my rockers and wanted some input,im not looking to spend a fortune, i was looking at the summit catalog and saw they had harland sharps and a summit version for around 350. my car is a ls1 head and cam (mid 240 duration close to .650 lift) and im shifting the car around 7k. was wondering how much i could benifite vs stock rockers,obviously i know theres going to be a gain,but ive heard of guys useing stock rockers and being fine so i was wondering if it'd be worth the switch and are the harlands or summits a good way to go? id pick up what prolly 10-15hp maybe? is that whp?
The stock rockers are very good and generally not worth upgrading. Yes you should see some gains by upgrading. If you get 10rwhp I personally would be happy.
There are other options like Yella Terra as well. I personally used Harlands in my 408. If I was not using trickflow heads I dont know that I would have upgraded. I would have at least done the trunion upgrade though.
There are other options like Yella Terra as well. I personally used Harlands in my 408. If I was not using trickflow heads I dont know that I would have upgraded. I would have at least done the trunion upgrade though.
you can also upgrade your trunions in your stock rockers to keep costs down and never have to worry about those needle bearings.
http://www.compcams.com/information/...yID=1508422545
http://www.compcams.com/information/...yID=1508422545
^I thought there was an article in GMHTP regarding the stock rockers putting excessive for/aft load on the valve tip an causing valve guide wear due to the lack of a roller tip. Not sure on how REAL those concerns are though.. I've thought about upgrading to RR's as well, but I'll wait till the TF heads find their way under the hood.. 
^I thought there was an article in GMHTP regarding the stock rockers putting excessive for/aft load on the valve tip an causing valve guide wear due to the lack of a roller tip. Not sure on how REAL those concerns are though.. I've thought about upgrading to RR's as well, but I'll wait till the TF heads find their way under the hood..
IMO for an aftermarket RR YT UL's are the best value with Jesel being the best period...
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There is a lot of myths out there when it pertains to stock rockers.
The only thing that holds back the stock rockers is the open needle bearing casing. If you get the trunnion upgrade on stock heads the stock rockers are good for a .650 lift with no issues. You will not see any HP gains from changing out your rockers. The stock rockers arms though are pretty much bullet proof on stock heads.
You have to ask yourself if all the top builders like Lingenfelter and such use stock rockers on their top of the line builds there something to be said for them.
The only time I would advise going with aftermarket rockers is if your doing an after market head like a TF or such. Other than that there is no need.
The only thing that holds back the stock rockers is the open needle bearing casing. If you get the trunnion upgrade on stock heads the stock rockers are good for a .650 lift with no issues. You will not see any HP gains from changing out your rockers. The stock rockers arms though are pretty much bullet proof on stock heads.
You have to ask yourself if all the top builders like Lingenfelter and such use stock rockers on their top of the line builds there something to be said for them.
The only time I would advise going with aftermarket rockers is if your doing an after market head like a TF or such. Other than that there is no need.
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The stock rockers may work up to .650" lift but the wipe pattern usually sucks. The magazine article mentions the geometry limitations. During some upgrades and a cam (.612"/.617") swap last year, I checked the geometry with my stock rockers with my old cam and the new cam. They were all way off with both cams. Some high on the stem, some low. Installed Yella Terras, set the preload properly, wipe pattern is perfect on all valves. Now, there is not much on my LS1 that is stock anymore, and I spin over 7000rpm regularly so I care a lot about geometry.
I forgot to add; my heads are Cartek x4 243 castings, not TF's or AFR's.
I forgot to add; my heads are Cartek x4 243 castings, not TF's or AFR's.
Last edited by Goldfinger911; Feb 18, 2010 at 10:39 AM.
The stock rockers may work up to .650" lift but the wipe pattern usually sucks. The magazine article mentions the geometry limitations. During some upgrades and a cam (.612"/.617") swap last year, I checked the geometry with my stock rockers with my old cam and the new cam. They were all way off with both cams. Some high on the stem, some low. Installed Yella Terras, set the preload properly, wipe pattern is perfect on all valves. Now, there is not much on my LS1 that is stock anymore, and I spin over 7000rpm regularly so I care a lot about geometry.
I had a similar experience and spent hours on the work bench trying to get the stock rockers to provide a narrow pattern. I finally gave up and found I could set up the YT's quickly and the wipe pattern was 0.045" wide perfectly centered. I recently had them off for a pushrod change and the pattern was still perfect and where I set it. The OP has more lift then I was setting up at the time so it will likely be worse then what I found if checked.
Def good to know about wipe pattern,i dont know the most when it comes to rockers, i can get a really good deal for some comps at my work, i know there are alot of variations so, which comp rocker would you pick? golds?
I don't recommend the harlands at all I have had the rocker arm bolt snap off in the head, and my buddy had the pushrod break THRU the back end of the rocker.
get stock rockers and have them modified.
or YT's but I can't recommend the HS rockers anymore...
Chad
Chad
get stock rockers and have them modified.
or YT's but I can't recommend the HS rockers anymore...
Chad
Chad
Yeah, Lunati makes good **** indeed. I have the old school Yella Terras and Patriot Gold springs, and I love them. They clear stock valve covers and no valve float issues.
The ones shown here: http://www.ls1howto.com/index.php?article=21
The ones shown here: http://www.ls1howto.com/index.php?article=21
I would stay away from the stud mounted adj rockers. they can and will cause valve float issues if you spin 7k or more rpm. I was warned about them by tony mamo but i was not willing to get rid of my $400 comp rockers.
till the first time i spun it up 7200 and it sounded like it was going to explode before it shifted. went home swapped the stockers back in. thats the only thing i did.
took it back out and ran perfect to the 7200 sp in all gears. I run the afr 8019 upgrade springs on afr heads with the springs shimmed .040 from bind so it was not a spring issue.
a shaft mounted set up is the way to go.
till the first time i spun it up 7200 and it sounded like it was going to explode before it shifted. went home swapped the stockers back in. thats the only thing i did.
took it back out and ran perfect to the 7200 sp in all gears. I run the afr 8019 upgrade springs on afr heads with the springs shimmed .040 from bind so it was not a spring issue.
a shaft mounted set up is the way to go.
