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I have a question about the Yella Terra rocker arms.
When I installed them, two pair ended up with two dots on the rocker shaft showing, the other six ended up with the smooth side of the rocker shaft showing. Does it matter which side of the shaft is showing? I would think they probably put the dots there for a reason.
I checked out jmX's site -- great site by the way, I would not have done H/C by myself without it -- and he shows one pair installed with the dots up, the other 3 have the smooth side showing. The Yella Terra install directions mention nothing about what the shaft orientation should be. Just want to make sure I am OK before I finish bolting everything up.
Jeff,
I saw the exact same thing when I installed mine last week along with my H/C package. I looked at the seat area where the rocker bolt sits to see if it was different and didn't see any difference with the dots up or down. I installed mine with the dots down if it makes any difference to you. I only did this, because when they were sitting in the original packaging, the dots were down on all of them.
I didn't see any difference either, but I thought it was strange that one side has dots and the other does not. I am going to try to get ahold of Yella Terra to see if they have any input on this.
Speed Inc. sells them - at the link below, choose the year of corvette on the left and then valvetrain components. Then they're about halfway down the page. I know others sell them as well. http://www.ls1speed.com/index.cfm
HP gain is minimal. The Yella Terras have a roller tip that contacts the valve, where the stocks do not. Supposedly the stock rockers flex at high rpm's and the Yella Terra's don't. Also some have had the stock rockers lose their needle bearings, although this seems to be rare.
If you have a 97 or 98 with the perimeter bolt valve covers, you have to grind the valve covers to fit. I am in the process of doing that now and it is not fun. If you have a 99+, they fit without grinding.
Thunder Racing - $500
I installed them for the piece of mind that they will stay together more than the HP factor. I am sure that the reduces friction on the valve tip has to worth something along with the fact that they don't flex and i'll get a more accurate lift at the valve.