1.7:1 vs 1.8:1
12-12-2023, 11:55 AM
#1
1.7:1 vs 1.8:1
Hi there,
Has anyone changed the rocker arms in their LS3 with either Yella Terra 1.8 to 1 or Harland Sharp 1.8 to 1's. Did you get any real increase in hp or did either do damage to the valve train after the install. I did this on my old C5 LS1 and they did make an improvement. Not sure about the LS3.
Has anyone changed the rocker arms in their LS3 with either Yella Terra 1.8 to 1 or Harland Sharp 1.8 to 1's. Did you get any real increase in hp or did either do damage to the valve train after the install. I did this on my old C5 LS1 and they did make an improvement. Not sure about the LS3.
12-12-2023, 06:33 PM
#2
Le Mans Master
Hi there,
Has anyone changed the rocker arms in their LS3 with either Yella Terra 1.8 to 1 or Harland Sharp 1.8 to 1's. Did you get any real increase in hp or did either do damage to the valve train after the install. I did this on my old C5 LS1 and they did make an improvement. Not sure about the LS3.
Has anyone changed the rocker arms in their LS3 with either Yella Terra 1.8 to 1 or Harland Sharp 1.8 to 1's. Did you get any real increase in hp or did either do damage to the valve train after the install. I did this on my old C5 LS1 and they did make an improvement. Not sure about the LS3.
12-12-2023, 07:31 PM
#3
Last edited by grinder11; 12-13-2023 at 07:58 AM.
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old motorhead (12-13-2023)
12-12-2023, 07:45 PM
#4
Race Director
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1.8 ratio rocker arms will increase the stock 1.7 ratio LS3 cam lift of .551”/.525” .to. .583"/.556"
http://www.wallaceracing.com/rockercalc.php
Just my opinion, but a pretty good mod for someone that wants to keep the stock cam in the engine and has already installed a set of headers and a good dyno tune.
Here is a good set of LS3 1.8 ratio roller rocker arms: . Comp Cams ‘Ultra-Pro Magnum’ Roller Rocker Arms . . P/N: 1678-16
I would not use the OEM springs with these rocker arms .. A good set of springs would be PAC-1218 ‘Beehive’ Valve Springs
Replace the OEM valve stem seals at the same time your replacing the valve springs.
http://www.wallaceracing.com/rockercalc.php
Just my opinion, but a pretty good mod for someone that wants to keep the stock cam in the engine and has already installed a set of headers and a good dyno tune.
Here is a good set of LS3 1.8 ratio roller rocker arms: . Comp Cams ‘Ultra-Pro Magnum’ Roller Rocker Arms . . P/N: 1678-16
I would not use the OEM springs with these rocker arms .. A good set of springs would be PAC-1218 ‘Beehive’ Valve Springs
Replace the OEM valve stem seals at the same time your replacing the valve springs.
12-12-2023, 08:13 PM
#5
Race Director
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And with the Comp Cams 1.8 ratio roller rocker arms you don't need to worry about the needle bearings falling out of them like what sometimes happens with the OEM rocker arms.
12-13-2023, 08:24 AM
#6
Le Mans Master
Absolutely agree. I've also wondered about the effect on valve guide seals on older engines. Say your valve lift has been .560" for 75,000 miles, and all of a sudden you're now at .580". Does that increase seal wear now, because there may be a slight lip on the valve stem where it never entered the seal before, and now it is?
WAY above my level!
12-14-2023, 12:09 PM
#7
Le Mans Master
Absolutely agree. I've also wondered about the effect on valve guide seals on older engines. Say your valve lift has been .560" for 75,000 miles, and all of a sudden you're now at .580". Does that increase seal wear now, because there may be a slight lip on the valve stem where it never entered the seal before, and now it is?
