340 mopar rocker arm/shaft strength
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340 mopar rocker arm/shaft strength
If I were to have a hyd. roller 340 (410 ci stroker), built on a budget, would stock rocker arms be fine at 140/closed 365/open spring pressure? Camshaft 234/246 on a 110, .550/.550. Wont be turned more than 6000 rpm max. Likely will peak about 5200rpm, and shift no higher than 5500-5800 tops. If stock rockers wont work, what is adequate?
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Re: 340 mopar rocker arm/shaft strength
This all depends on what your stock arms are. If they are the stamped steel type then no. If they are the adjustable type that take a ball and cup pushrod, then yes. You did not state which type of stock rocker arms you had. I hope this helps.
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Re: 340 mopar rocker arm/shaft strength
I wouldn't do it. A set of 273 rockers is cheap. I wouldn't run stamped steel rockers on my lawn mower.rewguy wrote: ↑Mon Nov 20, 2017 7:20 pm If I were to have a hyd. roller 340 (410 ci stroker), built on a budget, would stock rocker arms be fine at 140/closed 365/open spring pressure? Camshaft 234/246 on a 110, .550/.550. Wont be turned more than 6000 rpm max. Likely will peak about 5200rpm, and shift no higher than 5500-5800 tops. If stock rockers wont work, what is adequate?
Re: 340 mopar rocker arm/shaft strength
Aftermarket rocker shafts are a must have. The stock shafts go eggshapped when torqued. Ever wonder why the stock rockers fit so loosely?
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Re: 340 mopar rocker arm/shaft strength
. I wouldn't run stamped steel rockers on my lawn mower.
my 18 hp B&S powered sears riding mower does have stamped steel rockers.
my 18 hp B&S powered sears riding mower does have stamped steel rockers.
Re: 340 mopar rocker arm/shaft strength
My sbm dirt track motor has stock adjustable rockers on it... spring pressures are about 140/400 and they look good. I also have a set of T and D's that are brand new that the engines PO didn't feel the need to install as he didn't have any trouble with the stock ones.
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Re: 340 mopar rocker arm/shaft strength
Where is a good place to buy the adjustable 273 stock style rocker arm? And it oils through the shaft the same way as the stamped 340 version does?
Re: 340 mopar rocker arm/shaft strength
Do Mopar rockers have factory spacers or do the rockers have springs and the nylon buttons that keep them spaced. My 350 Buick rockers were set up that way. I would Imagine the adjustable rockers with some solid spacers made up would work rather well.
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Re: 340 mopar rocker arm/shaft strength
statsystems wrote: ↑Mon Nov 20, 2017 8:19 pmI wouldn't do it. A set of 273 rockers is cheap. I wouldn't run stamped steel rockers on my lawn mower.rewguy wrote: ↑Mon Nov 20, 2017 7:20 pm If I were to have a hyd. roller 340 (410 ci stroker), built on a budget, would stock rocker arms be fine at 140/closed 365/open spring pressure? Camshaft 234/246 on a 110, .550/.550. Wont be turned more than 6000 rpm max. Likely will peak about 5200rpm, and shift no higher than 5500-5800 tops. If stock rockers wont work, what is adequate?
What kind lawn mower do you got!?!
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Re: 340 mopar rocker arm/shaft strength
Factory rockers will fit loosely with aftermarket r/shafts, just as they do with factory shafts. Purposely designed that way to oil the rocker/shaft interface.
Re: 340 mopar rocker arm/shaft strength
The factory 273 adjustables use spacers to separate the rockers. On a set employed recently, I used the Huges Engines Shim Kit # HUG1700 in addition to the spacers to align the rockers and take up the clearance. Worked perfectly, and runs relatively quiet (for a solid flat tappet)
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Re: 340 mopar rocker arm/shaft strength
Those stock Mopar shaft mount rockers are pretty darn foolproof if installed correctly and I think they will work just fine with those loads. I think that other areas of the valvetrain will cause more trouble than the rockers if you switch it to a hydraulic roller. The pushrod angle at the lifter will become even more severe and you'll probably have to do some work on the heads where the pushrod passes through.
Re: 340 mopar rocker arm/shaft strength
As already stated, hydraulic roller means wicked pushrod angle requiring a lot of work to clear heads in that area. Just be prepared ahead of time with mock up if you go in that direction.
Re: 340 mopar rocker arm/shaft strength
Yes they will because the aftermarket shafts are the same diameter. Got an education years back. Installed bushings in Isky rockers for a BBM. Using the stock shafts, the rockers locked up after torquing. Put in Comp 8620 shafts problem solved and they did not have to be sloppy loose.
Monty Frerichs
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