aluminum heads with oem rockers?

-

rigger3006

Well-Known Member
Joined
Aug 6, 2013
Messages
866
Reaction score
251
Location
north america
are there any aluminum heads out there that one can use oem shaft rockers?mild build 340, 474/280 mp cam
 
had stock rockers on my eddy heads.


DSC09923.jpg
 
This is a great question! I was thinking that I would have to buy new for my 390 stroker with LAX heads. Sounds like stockers are ok with "most" aftermarket heads.
 
If the heads are set up for standard Mopar SBM shaft rockers, they will take the stockers. But it's also about stress on the rockers; the stockers can only take so much. That's not determined by what they are mounted to; steep cam ramps (Voodoos and XE cams), higher lifts, high RPM's, and heavy springs will push them towards overstress/breakage.

The OEM's survived in the 340's with mid 400's lifts, slow cam ramps, and moderate valve spring rates, so take that as a clue to what they can take. There is a reason that the heavy duty MP versions were made.....
 
yes the stock rocker will work on most aluminum heads, will they be reliable, maybe, maybe not.
the not should make you spend the extra coin for some roller rockers or iron adjustable
 
key to making stock rockers work- when we had to run them due to rules etc
use lash caps to spread out the load and get rocker centered on valve stem with shaft shims

Do the mid lift geometry procedure and
raise shafts as necessary with shims on pedestal under shaft (or machine off pedestal and make new stands in the right place)
run Magnum/ AMC lifters and hollow pushrods to oil rocker cup- a known problem spot- do geometry B4 ordering pushrods
run a HV pump and not restrict oil to the rockers- also cools the springs BTW new beehive springs make less heat than dampner ones and much less than duals
case hardened shafts- hard chrome if iron or bushed iron rockers (ok also with stock but not with rollers) tha's tripple plated, copper,/brass/ nickel bhard- grind, chrome
the nickel does the work, Iron and bushed iron rockers must be not only bored to correct size but honed for oil retention

rigger asks: roller rockers that are non adjustable???
yes- for some oddball motors where you have to use adjustable pushrods- and these are usually no fun to adjust used to see them on early hemi etc
and some roller rockers for mopar are/ at least were- so bad that they might as well been non adjustable
many with angle of the adjuster way off from the line of the pushrod, or the location of the pushrod ball wrong
best rockers will have cup on adjusters and ball end pushrods some will have larger cups and balls
always use 3/8 (or larger) heavy wall pushrods if your heads allow
 
-
Back
Top