Stock rockers on Edelbrock RPM heads

[stickman77]

Can you use stock stamped steel rockers with the Eddy aluminum rpm heads. It's a stock 440 with a comp XE268 cam .477/.480 lift. Weekend driver, not for race purposes.

 

[RT K_line]

When I bought mine I recall that you could use all stock components with them.

 

[Garys1969RR]

I looked into this awhile back, and was told by Edelbrock tech that you can use the stock rocker gear with cams up to .500" lift. And I have heard of guys using the 509 cam on them with stock rocker arms. I use the stock rockers with my 509 cam on a set of 915s, and they work great!

 

[Wookie316]

http://www.hotrod.com/how-to/engine/1412-how-you-can-build-a-stout-537hp-street-440/

 

[Cranky]

Stock stamped or the Mopar Performance stamped heavy duty rockers?

 

[moper]

Stock ones, or the MP/Mancini thicker ones will work fine. But - you must pay careful attention to pushrods. You should plan on measuring and having custom ones made to get the right preload on the lifters.

 

[Rocketman]

Can you use stock stamped steel rockers with the Eddy aluminum rpm heads. It's a stock 440 with a comp XE268 cam .477/.480 lift. Weekend driver, not for race purposes.

My mechanic advised me not to when we built my motor, we went with the comp roller rockers

 

[Cranky]

I like adjustables myself but imo, roller rockers on a mild cam is overkill and a waste of money. On the stockers, I would use at least the heavy duty ones. They have more meat and will not flex nearly as much as a factory stocker....and use the recommended valve spring for the cam and no more. A buddy and I stuck in a .480 lift cam into a teen and we were turning it 6200. There's not that many passes on them but if they weren't up to the task, I would think they would have let us know by now.....

 

[dvw]

I've done it. First motor went 9 years and the flattened a lobe (not rocker related), replaced with a hyd roller and ajustable rockers. 2nd Motor's been running fine 4 years. Comp [email protected] hyd cam
Doug

 

[cryplydog]

maybe you could find you a used set of Crane or Isky adjustable rockers. I think it would be a definite plus in performance and you would have adjustability?= win/win

 

[BBishere2]

I'm looking at the same thing - going to use a Comp Cams XE275HL - .525 lift cam. After reading a couple articles of builds, one pushed them up to .545 lift with no problems, I'm planning on buying the rocker arm and shaft kit from Mancini and using the stamped steel ones and the Edelbrock Performer RPM heads. Looks like the valve springs on the heads have less pressure than the Comp springs do, so I'll use them.

 

[lewtot184]

two problems with stamped steel rockers; people tend to use too much spring pressure and rocker geometry issues with high lifts. if a person can stay to the moderate side i don't see anything wrong with using them, and the 1.38 ratio ratio thing is myth at best or an out right lie to get you to buy something you don't need.

 

[moper]

BBish - you really should replace the springs and run adjustable rockers if you want to run that camshaft. You are asking for valvetrain problems and/or a wiped cam by combining that cam with those parts.

Or - run a smaller less aggressive camshaft. The HL lobes are a bit faster and you need more pressure with them - not less. You risk the lowering of the rpm window the cam works in, and the camshaft itself if the lifters experience a loss of control and contact with the cam lobe at any point.

 

[Wookie316]

Run correct valve train or learn an expensive lesson like I did.



This was a combination of too light a spring and an improper installed height. Needed much more pressure for the cam I was running. Because I was keeping tabs on my oil and cutting my filters apart after every race, I caught this before I lost everything.
The cost to fix it correctly more than doubled what I should have had to spend if it had been done correctly the first time.
Take the time to learn from those who understand spring pressures and valve train and save some head ache and money.
I wish I had.

 

[Garys1969RR]

We put an XE 274 comp cams with .488/.491 lift in my sons 383. We're using stock springs that were on the 67 440 (915) heads. Stock rocker gear, 3 years running, and no probs so far. Pretty sure the stock 440 Magnum cam is around .480 lift, so you're at what a stock cam would have. The Eddy heads have springs that will accomodate .500 plus lift at the valve. If anything, those heads would have higher spring pressures than a stock factory head.

 

[moper]

The XE series is a slower lobe than the XE-HL series lobes because the XE series works with the smaller lifer diameters and the HL is .904 Mopar only. So you have a good bit smaller cam than the 285HL, and the HL series needs a double spring. The XE274 calls for the single spring that is the same spec as the RPm spring. Honestly - you've had no problems, but that doesn't mean you "got it right". Because if you have stock Magnum type springs on it, it's not making near what it could for steam, stamped rockers or no. I find it crazy that the manufacturer tells your machinist what has to be run and they ignore it.

 

[BBishere2]

BBish - you really should replace the springs and run adjustable rockers if you want to run that camshaft. You are asking for valvetrain problems and/or a wiped cam by combining that cam with those parts.

Or - run a smaller less aggressive camshaft. The HL lobes are a bit faster and you need more pressure with them - not less. You risk the lowering of the rpm window the cam works in, and the camshaft itself if the lifters experience a loss of control and contact with the cam lobe at any point.

One of the Mopar magazines ran that same camshaft on 906 heads with the stock springs for that head along with the rest of a stock valve train and they had no problems - there was no long term follow-up to the story to let us know how it lasted or if it blew up. I've spent quite a bit of time researching this. Time will tell.

 

[Garys1969RR]

In answer to your question, stickman77, yes you can run stamped steel rockers with the XE268 cam, and the Eddy RPM heads. Lots of guys have used higher lift cams with those heads and stamped rockers with no probs. That cam lift is similar to the Magnum cam, and isn't considered to be a hi lift cam. Follow the cam manufacturers spring pressure recommendations.