Camaro Research Group Discussion > Originality
Questions about "O" Rockers 3974290 for 69 Z/28
jdv69z:
I would think it would be like a cam button, for thrust loads which would be from any for and aft movement of the cam and gear.
69Z28-RS:
I'm not familiar with that part, or PN, either, but here's an old ebay listing with a photo. I don't recognize the part, and it's identified as a part for a 454 Mercruiser-Quicksilver?? Could that be an error in Hooper's book?
http://www.ebay.com/itm/GM-GMC-3887871-CAMSHAFT-THRUST-BEARING-FOR-MERCRUISER-454-QUICKSILVER-23-49124-/181326780245?nma=true&si=kA4%252FKicFYZKSnm4atRU9XiLTZXU%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557
Bryan, re the 140 cam.. back in the late 60's and early '70's, I knew a couple of folks who tried the 140 cam, and neither realized any benefit from it nor were they happy with it (in street cars, used heavily for street racing). I suspect your experience would be the same or even worse for how I suspect you'll use your car.
How was Super Chevy Memphis? :)
Gary
Bryan302:
Hi Gary,
After seeing that picture of the part, I don't think it is a relative part of the 140 grouping. There is not even a place I can think of, it could go, especially related to the timing gear.
Memphis was very good. The Z parts were thin. I saw five DZ carbs, six 472 intakes, a 68 BV rearend, three or four 403 bell housings, one each 668 and 456 pulley, one endura bumper, a nice set of guages, a pair of non drip valve covers, and a early set of 69 Z exhaust, and that was it. For someone, that would have been something to dance about, I didn't find squat. I did pick up a good 367 starter, but not my date.
Thanks for finding that part. Maybe someone will know about it.
Thanks,
Bryan
luv2sixty9:
Yes, the "O" Rockers can be used with the 140 Camshaft.
JohnZ:
--- Quote from: Bryan302 on April 14, 2014, 06:06:43 AM --- My question is.. Are the 3974290 "O" rockers arms good enough to be compatible with and intended to be used with the "140" cam?
If a person were to build a set of 3974290 rocker arms from the current sources of NOS parts, ebay, camaro shops, etc. Would he still get the same "O" rocker out of the current 3974290 box? Are they still made the same, heat treat, hardness, etc. Do the new ones still have the "O" on them?
Does anyone know if the new replacement part number of 10089648 gets you an "O" rocker? My dealer says that the 10089648 is a direct replacement for the 3974290, but I kinda doubt it!
What aftermarket brand such as Crane or Manley, with the part number, would replace the "O" rocker?
Please advise and suggest.
Thanks,
Bryan
--- End quote ---
GM hasn't manufactured the "o" rocker arm for decades - the only stamped rocker arm available from GM these days is the "guided" rocker with the "ribs" to keep it centered on the valve stem, and you can't use that rocker with solid lifters.
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