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Old 09-19-2005, 07:02 PM   #1
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(Search function sucks) is there an advantage to using rockers from a L27 or another motor? I know you have to drill the pedestals but are they a better duration? what is the stock duration of the LN3?
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Old 09-19-2005, 07:21 PM   #2
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I know about the www.seriesoneperformance.com rockers but can I make the others work for a possible performance upgrade?
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Old 09-20-2005, 05:37 AM   #3
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Not from a ratio difference. They are all the same ratio, but the 93+ L27 rockers have a roller pedistal. 5hp maybe. Not worth the cost of drilling them out.
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Old 09-20-2005, 09:00 PM   #4
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how hard can it be? 5 hp for just getting some at a JY. it maybe worth it
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Old 09-20-2005, 10:01 PM   #5
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5hp for getting some at a junkyard and drilling them out to whatever size they should be... ours have larger studs. MAY make the engine rev smoother... but honestly the cost may be better spent on some aftermarket rockers... even though the L27 rockers are cheaper.. performance gains are better on the aftermarket ones considering our cams have extremely low lift...
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Old 09-21-2005, 12:25 PM   #6
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the problem is the cam, I am not about to tear the motor out, and the price tag on those aftermarket ones are to much, so my only alternative is drilling out the roller rockers. damn. well 5hp is better than nothing
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Old 09-21-2005, 04:07 PM   #7
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Personally, I would check with the local junkyard on how much some 93 b'ville rockers are [NOT 92!!!! those aren't rollers] and then go to the local [trustworty] machine shop and check how much it would cost to drill them out... to 9/16" [please someone confirm this!]. If it'* $50 out the door, I wouldn't do that. I'd spend that $50 on a 93 octane tune and a tank of 93 [well, with gas prices these days, that may only be a 1/4 tank with the leftovers]. You can even get multiple programmings, to have like an 87 octane tune, and a 93 octane tune... I looked into it and GM tuners can do that with a little extra cost [only pay for the first tune, btw] for the unit which switches the programmings.
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Old 09-21-2005, 10:13 PM   #8
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Be careful to check the position of the tip of the later model roller trunion rockers before you buy. I bought one some years ago and checked it on the engine. Even though the trunion can be drilled out to fit the stud, the tip of the rocker is too long and overhangs the valve stem. In other words the geometry is wrong. The stud in the head will need to be moved closer to the pushrod side for them to work properly on an LN3 engine. It wasn't obvious just comparing them side by side, I had to drill it out and mount it to see the problem. I have seen drop in roller trunnions for Ford engines that have a similar system to ours but I have never had the opportunity to check to see if the radius is correct for our rockers. Theoretically you could get an adjustable valvetrain with either change but that in itself has little benefit unless the heads or block have been shaved a fair amount.
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Old 09-21-2005, 10:52 PM   #9
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sounds like you got a series 2 rocker... the L27 heads are identical to the LN3'*... this has been said, and i believe those who said it.

Were the rockers full rollers? like kinda aftermarket looking rockers?
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Old 09-23-2005, 12:06 AM   #10
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Could be series II? They have a roller pivot only, standard rubbing type of valve operating tip. Rockers were a cast or powder metal construction, not a stamped steel rocker. Purchased from the local Buick dealer, definitely not aftermarket.
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