will stock rockers work with larger springs?

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moparmatt19

moparmatt19

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I have a set of 596's fully ported with 2.02 1.60's ok original plan was running a fairly healthy solid cam,but right now I need to run a small hyd lunati cam 230/.480 im using a set of bb springs with installed height of 1.8 and diameter of 1.5. My solid lift dual springs were set at that height so thats why I needed the taller spring for the hyd. And I had a set of bb single with damper setting on the shelf that would work at that height and keep the pressure right... ok to the point.. shew finally right? Ok will the stock stamped rocker arms work and clear the larger springs ? I hope so! The heads are still at the machine shop bc I haven't had a chance to go get them or I could check for my self lol. I got extremely poor in the middle of this project and cant afford the $600+ rocker arms and 3500 stall converter I need for the solid lift cam and i need this engine back in the Dakota so I can drive it. Lol yes I hit a bump and got stranded with only my projects left for vehicles. And this Dakota is the closest one to be street worthy. "Gotta love divorces"! Later down the road when I can buy the rocker arms and converter i can just change the cam and springs out to the solid lift cam. Any comments are welcome ! And thanks!
 
340 springs were that big, about 1.50 inches, and 340 rockers were clearanced from the factory. I've had to clearance stock hydraulic as well as 273 mechanical rockers to use them with 340 stock springs. You can do it yourself with a bench grinder or have the machine shop do it, just do not get carried away... as always double check everything before buttoning it all up.
 
340 springs and Mopar iron rockers. I had to clearance them. I need to change to beehives or go back to the stock type springs. How about some #901 Comp springs? I need to go back and look at your build. tmm
 

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But what about the Stamped stock rockers? There pretty thin. I know there not accurate and are like 1.45 ratio but its only going to be temporary until I can get the Hughes engine rocker arms
 
Also im thinking the 340 installed height was like 1.64 or something. Mine is 1.8 which makes less clearance. What do ya'll think?
 
La valve spring installed height is about 1.69 in for heads in good shape. So maybe .11 inch difference. How did you get to 1.80? Valve? Retainer? The OD of the spring just gets less than a eighth of an inch higher. Do you have everything? Did you mock it up? Nothing weak about factory rocker arms. As I said before, the factory ground clearance into the rocker arms on 340's.
 
I am lost. Why do you need such a large installed height? That small Lunati doesn't need all that. I would lose the big block springs. The correct installed height for a stock/mild/moderate small block is around 1.625". You're talking about almost another 1/4" of installed height. That cannot have a good effect on geometry.
 
I used a set of longer stem ferra race valves. I think there 0.150 longer or so, cant remember for sure and a set of comp cams retainers with 10 deg locks. Installed height came right at 1.8 before we even cut the spring seat. Worked perfect.like I said was originally going to run a 248/252 .563 .0572 solid life cam and the spring height needed to be 1.8 . The comp is calculated 10.1.5 to 1 with iron heads
 
I guess you could try the stock rockers, but they are known for failure at the pushrod cup with increased spring pressure.
 
X2...

If you alter your installed height and valve length, you should probably correct your geometry...can you not wait to put all this together?
 
I wish I could wait. But I need the truck for about a month.thats all. I know the geometry will be off but its only temporary and probably on for around 1500 - 2000 miles worth. After that I will fix it all with the right stuff and the intended cam.
 
You could run lash caps temporarily. That could help with the geometry.
 
I'd be mocking it up and checking geometry and clearances. Check valve to piston clearance to boot with the big cam.
 
Rustyratrod.. the only reason im using the tall installed height is bc the head were set up for large double springs for the larger solid cam first. I cant make that any smaller now. I used a old head I had and mocked it up. Seems like the rockers will wipe on the stem fine. I think if I shim the shafts it will help a lot. How much can you shim them safely?
 
Your going to have to buy push rods and play with lifter preload and still not make it. Them stamped rockers are not going to like your spring pressure either. Either wait or change out to stock length valved heads.
 
I'll throw my 2 cents in: I'm gonna guess that at your installed height of 1.8 inch, stock rockers are gonna hit hard and no amount of shimming will fix it.

Years ago I did up a pair of "J" heads with Ferra .05 long intakes and .075 long exhausts, springs (Comps, don't remember the number) retainers to work with .600 lift, installed height was 1.875 if foggy memory serves me right.

I layed a rocker assembly on a head to see what it looked like and the retainers ran into rockers so bad that the shaft wouldn't lay down in the saddles. The fix was new springs(smaller diameter), retainers, and keepers (.050 offset to push retainer down) and an installed height of 1.75.

Maybe you'll get lucky; I'll hope for the best.
 
You said you machined the spring pocket........just wider or did you sink the spring seat surface down some?
 
Just wider. We had to machine a couple of the spring pockets down to get them right at 1.8 but only like .005 -.007 not hardley any. The combination of the ferrea valves and retainers I got from comp put the height right at 1.8 which is what Hughes engines said there 1111 springs needed to be for my cam.
 
I plan on using the rockers that Hughes sells. Ive heard good things about them. I knew the installed height sounded tall for a small block but thats what they told me. I sure hope there rockers will work. Bc i have a lot of money and even more time in these heads. I was just hoping I could run my hyd cam for now instead of the larger solid lift cam,but its not looking like I will be able to :(
 
Thanks guys for your help. I decided to just bare it and order the Hughes rocker arms. I have a valve machine so if need be I can grind the stems down a few thousands and shim the shafts. I believe I will be fine then.
 
I know this is late but I have a similar problem with only .100 long valves, the only way it can be fixed is to machine down the rocker stands and install taller shaft stands like on the w-2 heads or put std. lengths valves back it.
 
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