Olds BB adjustable rocker arms conversion

M

Mattyp77

Not-quite-so-new-guy
Nov 20, 2014
13
0
1
#1
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.
 

Attachments

olds307 and 403

olds307 and 403

Comic Book Super Hero
Oct 14, 2008
3,446
820
113
Melville,Saskatchewan
#3
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

Canon_Mutant

G-Body Guru
Aug 15, 2015
909
649
93
#4
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.
 
fleming442

fleming442

Comic Book Super Hero
Dec 26, 2013
3,958
1,915
113
#5
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.
 
olds307 and 403

olds307 and 403

Comic Book Super Hero
Oct 14, 2008
3,446
820
113
Melville,Saskatchewan
#6
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.
 
wskirvin

wskirvin

Greasemonkey
May 22, 2017
114
85
28
Indianapolis, In
#7
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

spidereyes455

Greasemonkey
Mar 6, 2013
191
71
28
Northeastern PA
#8
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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