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I am interested to learn if anyone has actually installed Competition Cams Pro Magnum or Hi-Tech Stainless rocker arms on a big block and what, if any, fitment problems were created as far as the subsequent installation of STOCK valve covers, with or without drippers. Just to be clear, I am talking about the ROLLER BEARING FULCRUM-TYPE Pro-Magnum or Hi-Tech Stainless rocker arms and NOT the PIVOT BALL FULCRUM Magnum type, roller tip rockers offered by Comp Cams. The roller bearing fulcrum rockers require the use of "poly-lock" type rocker nuts which rise above the rockers and can create valve cover interference.
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In Appreciation of John Hinckley -
Re: Comp Cams Pro Magnum Rocker Arms
Hi Joe - yes, I have a set of these I installed on my crate LS6 454, on the aluminum open chamber heads that were available until the mid 1990's. I have a set of the GM flash chrome valve covers with drippers, and I made it all work, using the GM steel core neoprene clad reusable gaskets. On the LH side with the dent for the PB booster, I had to do some work on the poly locks in my metal lathe, to shorten the length, being careful not to cut them too short and have the hex section interfere with the body of the rocker. It came out fine. I can probably pull a cover and mike the poly lock length if you need me to. I really was glad to fit these rockers under the covers, it took some tweaking to figure it all out. These were the full tilt pro magnum roller fulcrum and roller tip units that run around $300 a set, which is what I believe you are after...Craig -
Re: Comp Cams Pro Magnum Rocker Arms
Craig-----
Did you use the lock nuts that are supplied with the rockers or some others? Also, are the valve cover gaskets that you're using GM #14085759?In Appreciation of John HinckleyComment
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Re: Comp Cams Pro Magnum Rocker Arms
Joe - I believe I used the suppled nuts, and I think that is the gasket I used. I will check....I set you some shots a minute ago that show the cover style...CraigComment
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Re: Comp Cams Pro Magnum Rocker Arms
Joe - I no longer have the wrapper for the gaskets, I thought I did. They are the units that are black neoprent with I believe aluminum cores, with serrations on the sealing faces. Very very nice gaskets. Seems like they are about 1/8" thinck as I recall. I found one poly lock that I overcut slightly and was interfering with the body of the rocker on full lift (with the 4362 cam in the LS6). I sent you photos of that polylock to compare to yours, it is 0.775" overall length, but as I said, I am pretty sure it is too short...CraigComment
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Re: Comp Cams Pro Magnum Rocker Arms
Joe - I looked the gasket you mention up on gmpartsdirect.com and the list is $30.44. Did these drop in price, seems like when I bought them in the mid to late 90's they listed at $32 or so each...usually this stuff increases in price. Maybe these are different...not sure without seeing one...CraigComment
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Re: Comp Cams Pro Magnum Rocker Arms
Craig-----
I don't know the previous price profile of these gaskets. However, I think that they're the same ones that have been available for 15 years, at least, so they're likely the ones you have.In Appreciation of John HinckleyComment
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Re: Comp Cams Pro Magnum Rocker Arms
Joe- I sent you the shots of the rockers with covers off. I am pretty sure now that I had to cut all the polylocks uniformly, and they wouldn't clear the GM covers without the mods. I don't think the PB squash/rake area had anything to do with the clearance issues. As you commented in your note the ARP polylocks may not be the same if they have a smaller hex area. I think the poly locks are designed to allow a large fulcrum swing for very high lift cams, and hence, were long so the hex would clear the clearnace slot in the body of the rocker. By cutting the poly locks shorter, I was able to allow them to clear the covers, but not restrict the lift limits with my stock GM 4362 cam with 0.520 lift....I did note that the limiting factor was on the exhaust valves, the poly locks easily clear the intake rocker arms due to the valve geometry difference...CraigComment
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Did you trim the round end..What about 327?
Craig,
I assume you trimmed the round end and not the Hex. I'm going to attempt similar surgery on a set of poly locks to install Harland Sharp rollers under a set a 7 fin cast alum covers on my 327 small block.
Has anyone attempted this? Are thicker 5/16" metal core gaskets required?
tcComment
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Re: Did you trim the round end..What about 327?
Tracy - yes, I trimmed the round end. I will send an email, if you respond (so I get your email address) I will send you a picture of the short polylock...CraigComment
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Re: Did you trim the round end..What about 327?
I would also be interested if anyone has done this to a 327. When I rebuilt my 327/350 a couple of months ago I used the Pro-Magnums. I have had interference with the stock valve covers from the polylocks. I have since purchased the magnum pivot ball fulcrum style, but would really rather use the pro magnums. I think the overall length of the supplied locks are right at 1 inch. I am thinking that if I have .100 to .125 trimmed off the bottom of the poly-lock, I should be able to make it work.Comment
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something is wrong here.....
there is no need to cut the Polylocks, if longer rocker studs are installed. If you use std. length rocker studs with the roller rockers, that is a no no, and just asking for problems, like bent push rods.
I was running Crower Stainless Steel rockers, the only thing I did was trim the tips of the drippers, did not have to shave the Polylocks.
George D.Comment
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Re: something is wrong here.....
George - please elaborate. I don't see how longer rocker studs will help...that would just move the allen lock screw higher up in the polylock. I used ARP studs with ground tops if I recall. I don't see why bent pushrods would result from using standard studs...CraigComment
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nope....
it will move the set screws deeper into the polylocks. The set screws should sit, a minimum 1/8" inside the polylocks, when tightened.
When I talk about bent push rods, trust me, I've been there, done that, and learned the hard way. Ever see a pushrod snapped in three places? But then again I'm running a solid roller with a .623 lift.
Craig, if you haven't had any problems yet, you've dodged the bullet, for the time being.
GeorgeComment
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Re: nope....
geo if they are going to cut the length of the poly locks the set screw should be located in the correct depth. just make sure that the tops of the studs are machined flat if you are using the stock GM studs to make sure the set lock screw has a solid seating place. geo is correct about making sure the locking set screw is not to far down in the poly lock because the threads can be stripped out witout enought engagement. also set the valve .003 loose,tighten the set screw and then tighten the last .003 buy just turning the polylock itself with a wrench as this will make sure that the polylock will not come looseComment
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