Olds BB adjustable rocker arms conversion

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Mattyp77

Not-quite-so-new-guy
Nov 20, 2014
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Hey guys I have an Oldsmobile 425 with stock A heads. I need to convert the top end to adjustable rockers without having to take the heads off for machining. The only kit I was able to find that I know fits that criteria for sure is the Harland Sharp S50026A. It's almost $600. Im sure it's a quality product and worth it but this is a stock motor and very low budget. Is there a cheaper alternative? I know some kits are cheaper but require drilling the rocker stud holes to 7/16. But they don't specify if that means you have to take off the head. I won't mind drilling and tapping if I don't have to take off the head.
 

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Oct 14, 2008
8,818
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Melville,Saskatchewan
Don't A heads have 3/8" bolts? I used Scorpion 1.72 sbf roller rockers and Comp roller tip rocker arms with 5/16" to 3/8" comp conversion studs. They kept backing on me the last time but worked ok the first time.
 

Canon_Mutant

Royal Smart Person
Aug 15, 2015
1,159
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Just for the sake of understanding what your end intent is, why do you think you "need" to do this? I'm not asking this to be a butthole, I am literally just trying to understand the "need" to do this on a stock low budget 425? If this is about putting a big wicked camshaft in the motor that actually requires roller rockers and the supporting hardware . . . PLEASE STOP! You will thank me! I understand having a budget or perhaps NOT having a budget. I am not there now but, trust me, I have been. The "entire" engine has to be able to take advantage of the lift and duration a performance camshaft can provide.
 
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fleming442

Captain Tenneal
Dec 26, 2013
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Just for the sake of understanding what your end intent is, why do you think you "need" to do this? I'm not asking this to be a butthole, I am literally just trying to understand the "need" to do this on a stock low budget 425? If this is about putting a big wicked camshaft in the motor that actually requires roller rockers and the supporting hardware . . . PLEASE STOP! You will thank me! I understand having a budget or perhaps NOT having a budget. I am not there now but, trust me, I have been. The "entire" engine has to be able to take advantage of the lift and duration a performance camshaft can provide.
True dat, yo! "Most" Olds heads are only good to around. 474 lift before needing work.
 
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Oct 14, 2008
8,818
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You will gain 0 in the power department with them. Unless you pushing over .500" lift, you can get away with the simple torque and go stock rocker set up. Although I have found some bridges don't put the proper torque on the stock rocker arms. Good thing I have a dozen spares lying around.
 
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wskirvin

Master Mechanic
May 22, 2017
324
423
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Indianapolis, In
Not sure if you are still looking, but Comp Cams has a kit with roller rockers, push rods, the studs, nuts and everything to set it up. I personally haven't used them or know if you can make them adjustable, part number is 1442-kit. May be worth a shot calling comp and seeing what they say.
 

spidereyes455

G-Body Guru
Mar 6, 2013
781
1,632
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Northeastern PA
The Comp cams kit is a complete bolt on and does convert it into an adjustable valvetrain, and is less than $300 at summit. Its also available for sb olds engines.
 
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