I build street rods on the side for fun. That includes rebuilding and modifications for any and all components, including engines. I have to contract out most of the heavy work that requires machining to a shop down the road, as there is no room in my garage for a boring machine or big lathe. I don't have a flow bench either, but the shop I use does, and the guy is VERY good at doing what I ask.
As for the shaft mounted roller rocker, you may want to just have a system built locally for your engine. I have not found anybody that offers a ready-to-use shaft for an inline 6.
There are a couple of ways to approach the issue. One of the best ways is if you have, or know somebody that has, a rocker geometry-checking setup, and then make the shaft yourself or have a machine shop mill one for you.
You are going to have to make a single shaft for all 12 roller rockers. It can be hollow or solid. It will have to be machined to the exact same outside diameter as the little short shafts that each rocker uses already. Of course the single shaft must be drilled for 12 studs, and each rocker position has to have snap rings to hold them in place. Take each rocker apart and reassemble them onto the single shaft.
Now that you have a single shaft, you will need to figure out how high to mount it. The height I'm talking about is how far above the spring seat the center of the shaft is located. Set the new shaft with rockers down onto the STOCK studs, and use the geometry checking equipment to find out how high the center of the rocker shaft needs to be above the spring seat. This requires that you have the block under the head with the cam installed that you are going to use with this combination.
Now there are a couple of brands of hi-performance roller rockers that come with pedestal bases, and the bases are something else that has to be made, unless you can find a source to buy them. I prefer to make them, so I know they are correct length and solid. The pedestals can be either round, rectagular or square. You will have to mill off the rocker stud bases just like if you were installing screw-in studs. That gives you a flat to set the pedestal onto. How much you mill off depends on how tall the pedestals are.
Finally, the pedestals should be held from rotating by a small pin installed between the base and the flat on the head.
It's a lot of work to build one of these, and for the street, really isn't worth it. In fact, I don't think it's worth it unless you want more than 2 HP per cubic inch, or about 600 HP from a 292, aspirated or turbo. Plain individual roller rockers will work almost as well up to about 6500 rpm, and often higher. And these engines should not be run at the 8000 to 9000 rpms that v8's and v6's operate at. What you don't get with individual rockers is the stability that allows each cylinder to get exactly the same valve timing as every other cylinder. For a turbo application operating for longer periods of very high boost and high rpm, a shaft system becomes desirable.
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David
newbie #4153
edit: I forgot to note that to build a shaft system, you have to start out using the type of roller rockers that have the adjustment screw over the pushrod. You can't build a good shaft system using the rockers intended for mounting only on studs and adjusted by polylocks.
[This message has been edited by just a six (edited 07-24-2003).]
