Pushrods and rocker arms availiable?
Okay, I'm gathering parts for my L79 66 convertible. My question are the original type Pushrods and Rocker arms still availiable from GM if so I need some part numbers? If not whats everyone using? I have an NOS L79 Camshaft and going with screw in studs and guide plate in the heads. Also whats everyone opinion on rods, aftermarket or use the original ones? If aftermarket which ones? I going with stock domed pistons. Thanks in advance, sincerely Brian
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Re: Pushrods and rocker arms availiable?
Brian-----
The original-type rocker arms were discontinued by GM years ago. They were replaced by self-guided rocker arms of GM #10089648. An engine set of these arms is available under GM #12495490. If you use these rockers, DON'T use guide plates. They're not necessary and will, in fact, create problems.
If you want to use original style rockers, use Crane Nitro-Carb rockers. These are non-guided type rockers and configured very much like originals (no original stamping marks on the rocker tip, though, and they're expensive)
Original pushrods are discontinued and replaced by GM #14095256. This is a welded-ball type pushrod. These are excellent, high quality, PRODUCTION-validated pieces but they cost about 16 bucks each, GM list, and are not available as an engine set; individual pieces only.
You can also use a GM Performance Parts pushrod which is generally configured as-original. These are available as an engine set under GM #12495491.
Quite frankly, if you're using flanged base, screw-in studs (which I HIGHLY recommend), I don't see why you'd be interested in otherwise completely original configuration. I'd recommend going with the GM guided rockers, no guide plates, and the 12495491 pushrod set.
Another alternative would be to use Federal-Mogul rebuild engine parts. These pieces are not necessarily the same as GM PRODUCTION pieces, even though Federal-Mogul MAY manufacture some of the GM PRODUCTION parts. However, they are high quality and are quite inexpensive. Federal-Mogul rocker arms in the original style are available and pushrods in the original style are also available.
As far as the rods go, if I was rebuilding the engine, I'd replace them. Most 1966 Chevrolet 327's used the "ultimate version" of the small journal connecting rods. However, they're still very much inferior to modern rods. GM no longer has available any connecting rods for small journal small blocks. Aftermarket are available, though. Something I'd check into is the availability of powder metal rods for small journal applications. I don't know if these are available yet but I had understood some time ago that they would be available. These are relatively light, WAY stronger than any original small block rod (including the 302 and 350 "pink" rods), very closely weight-matched out-of-the-box, and fairly inexpensive-----the best of all worlds IF they're available for small journal cranks.In Appreciation of John Hinckley -
Re: Pushrods and rocker arms availiable?
just a reminder that you should not use the self aligning rocker with solid lifter cams and also check to make sure the rockers do not hit the valve keys if the valve stem tips are not long enoughtComment
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Re: Pushrods and rocker arms availiable?
If the original pushrods/rocker arms pass a visual inspection - no galling or other signs or excess wear, there is no reason not to reuse them, but they should be installed in their same mating postions.
It sounds to me like you are being advised by some "engine builder". There is absolutely no need for guideplates even in you use the OE non-self aligning rockers.
Also, make sure you use the OE spec valvesprings - 3911068 or Sealed Power VS677. DO NOT use some aftermarket high rate spring. They are totally unecessary and all they do is load up the valvetrain and increase the chance of wiping a lobe.
As far as 327 con rods are concerned, I have discussed this in great detail a zillion times. Search the archives for Crower and Eagle.
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