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LS to AMC rocker conversion |
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Mopar_guy 
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Joined: Jun/07/2009 Location: Ohio Status: Offline Points: 4823 |
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 Posted: Mar/11/2014 at 6:34pm |
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Looks good! Since these will work, I might buy a set and put them in since they're pretty cheap.Thanks again for posting this!
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RASelkirk
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Joined: Oct/24/2012 Location: SETX Status: Offline Points: 235 |
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Posted: Mar/11/2014 at 6:53pm |
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There's a guy a couple hours from me (in Waco) occasionally selling used rocker sets, among other J/Y parts, on E-Bay. Search for username bding44, I saw he had a set the other day for $27.50. The trunnion upgrade runs ~ $135, but pay close attention to the retainer rings. If they're sheetmetal, you can buy some quality US-made rings for around $10 for 32 from Allen's Fasteners. They also happen have the absolute best price on anything from ARP...
Russ |
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'63 American 220 Sedan (under re-construction)
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jcisworthy
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Joined: Jul/23/2009 Location: North Carolina Status: Offline Points: 2805 |
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Posted: Mar/11/2014 at 7:15pm |
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Plus pushrods. If it turns out something less than 8" will work they will be cheaper.
http://www.ebay.com/itm/390786309638?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
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jcisworthy
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Posted: Mar/12/2014 at 2:51pm |
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Checked the geometry with the Comp Cams adjustable pushrods today and it looks like with a 7.950 long pushrod the lifter preload is about 1/8 turn, with an 8.000 pushrod it is between 1/2 and 3/4 preload. I found a push rod that measures 7.963 long, 3/8 diameter fits 1988-95 GM 231 cid with roller cam, cost is about 2 dollars each. Preload should be around 1/4 range with it. GM part number on the pushrod is 25532501
Also, I was told today that the school's 2012 Copo Camaro came from the factory with 630-640 lift range with factory needle bearing rockers no trunnion upgrade and ran 150 passes with over 200 seat pressure and over 600# open no issues, so these rockers should hold up well in most any engine and even better with a trunnion upgrade. What I said earlier about cams around .500 lift may not be accurate, possibly up to .600 without a trunnion upgrade. That would be .637 lift at the valve with these 1.7 rockers.
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tsanchez
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Joined: Jul/09/2007 Location: Arizona Status: Offline Points: 4303 |
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Posted: Mar/12/2014 at 2:55pm |
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Need to check geometry, not if its centered but because its not a roller it needs to rock across valve without scrubbing or it will destroy vale tips
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jcisworthy
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Posted: Mar/12/2014 at 3:11pm |
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Rocker starts just below center and sweeps further below center then back. About .150 distance or so. I checked it against the factory bridge and it was similar only little lower on the valve.
Everyone who runs this absolutely needs to check their combination. What I listed above may/should work with a stock of close to stock set up and maybe others I dont know. What ever the case, it looks like a pushrod length change in whatever you are running may be the only change needed to bolt on and run LS rockers on a bridge head.
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tsanchez
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Posted: Mar/12/2014 at 3:47pm |
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It should start from the intake side and roll across and at max lift be on the exhaust side, it cannot act like a roller and come back.
Just a note on stock ls1 the casting mark near the tip is right at 90 degrees from valve stem which means from the pics you posted you would need to mill the head to get the rocker lower for it to work at all and then you would need to install ls style small spring retainers to clear rocker.
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jcisworthy
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Posted: Mar/12/2014 at 4:20pm |
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I checked this set up on a used 401 flat tappet hydraulic cam and the factory bridge.
On the same engine and they left the same mark on the valve only a little lower with the LS rockers and the rocker does not hit the stock AMC retainer at any point with about .040 clearance at the closest point, eyeballing it.
I dont think there will be any issues running this set up as a bolt on but I may be wrong. |
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jcisworthy
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Posted: Mar/12/2014 at 4:32pm |
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Bottom line is everyone needs to check their own set up.
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jcisworthy
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Posted: Mar/13/2014 at 11:15am |
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Couple things to watch out for on the rockers. First, as rocker opens valve make sure the head of the cap screw does not contact the rib in the rocker. Second, make sure the stop in the rocker does not bottom out throughout the lift range.
I am going to try to mock up enough of an engine this weekend and check geometry closer I had very little time when I checked it on the 401 and it is now apart.
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