1.8 rockers
Thread Starter
Le Mans Master
Joined: Jun 2008
Posts: 5,284
Likes: 235
From: Rockledge FL
1.8 rockers
I've been trying to read all I can about swapping the OEM rockers in my ls3 for 1.8s. I understand it's good for decent HP bump and since I've had two corvettes prior that both lost needle bearings I'm definitely doing something on my newest car before it happens again. Is there a proven combo that works easily. I'm seeing pac 1219 springs and new pushrods are common with this swap but what brand rocker is easiest to install? Any install like stock or are they all the poly lock adjustable style?
Race Director
Joined: Mar 2011
Posts: 13,262
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From: SW Florida
2021 C6 of the Year Finalist - Modified
Installs just like stock ... I have a set on my supercharged LS3
Using the PAC 1218 'drop-in' beehive springs.
Attachment 48331316
Attachment 48331317
Using the PAC 1218 'drop-in' beehive springs.
Attachment 48331316
Attachment 48331317
Race Director
Joined: Mar 2011
Posts: 13,262
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From: SW Florida
2021 C6 of the Year Finalist - Modified
I am almost certain you will need either valve cover spacers or taller valve covers.
In my case, I used the Holley LS 'tall' covers ... don't get the standard size Holley covers since they are no taller than your OEM covers.
Pushrods ... You can use your stock 7.4" length pushrods.
Attachment 48331311
In my case, I used the Holley LS 'tall' covers ... don't get the standard size Holley covers since they are no taller than your OEM covers.
Pushrods ... You can use your stock 7.4" length pushrods.
Attachment 48331311
Burning Brakes
Joined: Apr 2010
Posts: 1,131
Likes: 126
From: Conway, AR
I am almost certain you will need either valve cover spacers or taller valve covers.
In my case, I used the Holley LS 'tall' covers ... don't get the standard size Holley covers since they are no taller than your OEM covers.
Pushrods ... You can use your stock 7.4" length pushrods.
In my case, I used the Holley LS 'tall' covers ... don't get the standard size Holley covers since they are no taller than your OEM covers.
Pushrods ... You can use your stock 7.4" length pushrods.
Race Director
Joined: Mar 2011
Posts: 13,262
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From: SW Florida
2021 C6 of the Year Finalist - Modified
Team Owner
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From: Long Island New York
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Race Director
Joined: Mar 2011
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From: SW Florida
2021 C6 of the Year Finalist - Modified
If you don't plan on replacing your stock cam with something bigger, changing to 1.8 ratio rocker arms will increase your stock cams lift .030"
No dyno sheet to prove anything, but that increase in lift is much noticeable.
No retune needed if all your doing is installing 1.8 ratio rocker arms.
No dyno sheet to prove anything, but that increase in lift is much noticeable.
No retune needed if all your doing is installing 1.8 ratio rocker arms.
Race Director
Joined: Mar 2011
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From: SW Florida
2021 C6 of the Year Finalist - Modified
Stock LS3 cam Lift with 1.7 ratio rocker arms: . . .551” / .525”
Stock LS3 cam Lift with 1.8 ratio rocker arms: . . .583" / .556"
http://www.wallaceracing.com/rockercalc.php
Stock LS3 cam Lift with 1.8 ratio rocker arms: . . .583" / .556"
http://www.wallaceracing.com/rockercalc.php
Thread Starter
Le Mans Master
Joined: Jun 2008
Posts: 5,284
Likes: 235
From: Rockledge FL
Stock LS3 cam Lift with 1.7 ratio rocker arms: . . .551” / .525”
Stock LS3 cam Lift with 1.8 ratio rocker arms: . . .583" / .556"
http://www.wallaceracing.com/rockercalc.php
Stock LS3 cam Lift with 1.8 ratio rocker arms: . . .583" / .556"
http://www.wallaceracing.com/rockercalc.php
Do the comp rockers need any type of shim for wipe pattern adjustments? I am reading shims under the springs are necessary if they don't torque to 22 ftlbs after zero lash in half a turn or less. Trying to find install instructions
Race Director
Joined: Mar 2011
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From: SW Florida
2021 C6 of the Year Finalist - Modified
No shims ... Just replace your OEM LS3 rocker arms with the Comp Cams 1.8 ratio fully roller rocker arms.
Tighten the rocker arm bolts to 22 Ft/Lb just like you would do with the OEM rocker arms.
simple- stupid
___________________________
You can use your stock LS3 valve springs, but I would suggest you use a set PAC-1218 springs ... They are a drop-in replacement for your stock LS3 springs and can 'safely' accept a .600" valve lift. (with more closing valve pressure and slightly better fully open valve pressure).
Will rev to 6,500 rpm without a single problem.
Tighten the rocker arm bolts to 22 Ft/Lb just like you would do with the OEM rocker arms.
simple- stupid
___________________________
You can use your stock LS3 valve springs, but I would suggest you use a set PAC-1218 springs ... They are a drop-in replacement for your stock LS3 springs and can 'safely' accept a .600" valve lift. (with more closing valve pressure and slightly better fully open valve pressure).
Will rev to 6,500 rpm without a single problem.
Instructor
Joined: Apr 2021
Posts: 130
Likes: 19
From: Norcross, GA (USA) and Prague, Czech Republic (Europe)
I can confirm. I have got the mentioned Comp Cam 1678-16 rockers with PAC1218 springs and billet valve cover spacer. Stock 7.4 pushods. Everything works perfectly. The only downside is that if you want to replace the cam with a bigger one in the future, you will be limited in lift. Which is exactly what I'm dealing with right now. If I had known, I would have taken stronger springs, perhaps PAC1219.
Le Mans Master
Joined: Dec 2005
Posts: 6,999
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From: Southeast TX
I can confirm. I have got the mentioned Comp Cam 1678-16 rockers with PAC1218 springs and billet valve cover spacer. Stock 7.4 pushods. Everything works perfectly. The only downside is that if you want to replace the cam with a bigger one in the future, you will be limited in lift. Which is exactly what I'm dealing with right now. If I had known, I would have taken stronger springs, perhaps PAC1219.
Thread Starter
Le Mans Master
Joined: Jun 2008
Posts: 5,284
Likes: 235
From: Rockledge FL
I can confirm. I have got the mentioned Comp Cam 1678-16 rockers with PAC1218 springs and billet valve cover spacer. Stock 7.4 pushods. Everything works perfectly. The only downside is that if you want to replace the cam with a bigger one in the future, you will be limited in lift. Which is exactly what I'm dealing with right now. If I had known, I would have taken stronger springs, perhaps PAC1219.
Thread Starter
Le Mans Master
Joined: Jun 2008
Posts: 5,284
Likes: 235
From: Rockledge FL
Damn well I guess it's all over but spending the money
Comp rockers
Pac1218 or 1219 springs
ict spacers
I've got arh headers on the way to jet hot for coating and an intake headed to gwatney for the rod mod so perfect time to do the rockers
Comp rockers
Pac1218 or 1219 springs
ict spacers
I've got arh headers on the way to jet hot for coating and an intake headed to gwatney for the rod mod so perfect time to do the rockers
Instructor
Joined: Apr 2021
Posts: 130
Likes: 19
From: Norcross, GA (USA) and Prague, Czech Republic (Europe)
I read somewhere, maybe in the reviews about the 1.8 rockers on the Summit site or something like that, that someone didn't use a spacer and it was ok, but I can't confirm. I haven't tried without it.
Thread Starter
Le Mans Master
Joined: Jun 2008
Posts: 5,284
Likes: 235
From: Rockledge FL
Race Director
Joined: Mar 2011
Posts: 13,262
Likes: 3,151
From: SW Florida
2021 C6 of the Year Finalist - Modified
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Last edited by Turbo6TA; Apr 18, 2023 at 03:48 PM.