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Ivan, ASE Certified Master Technician
Category: Chevy
Satisfied Customers: 4871
Experience:  ASE Master Tech. 20+ years experience. 9 years self employed. Expert on AUTOLAB Radio Show
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chevrolet corvette L98: Hello: I have a 91 corvette L98. I

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Hello: I have a 91 corvette L98. I am having trouble setting my rockers.they are stock non rollers.I have set them according to the GM service manual but still are noisy. As I was cleaning them I found a part number stamped on the inside..I have an equal amount of each number which are..VR329A91... AND...VR129A91...(8) eight of each...what I need to know is there one number for the intake and one number for the exhaust...they were mixed up during tear down so could not be put back in there same order.I have been working on chevy engines for years and have never been unable to set the rockers...Need help with this question...Thanks Jesse....
Hello fellow 91 Corvette owner. If the car runs use this procedure. With the valve cover off, set up a cardboard barrier so the oil doesn't spill. Lossen each rocket until they clack, then tightn them until they stop, then go 1/4 turn tighter. Do this on every rocker. That will make them as quiet as they can be.

Your JA Expert,
Customer: replied 4 years ago.

Hello: I have done this already, and have had no luck, why are there two different numbers on the rockers ...That is my concern half with one number an the other with another.....

Are you using a combination of 1.5s and 1.6s ?
Customer: replied 4 years ago.

Hello: No these are the stock rockers unless they were that way from the factory...This is a built for export it has different lights markers and mirrow would this make a difference

It shouldn't. Now I will say, the rockers will have some noise to them even as roller lifters. This is amplified a little due to the aluminum heads and valve covers. I will do a little research on those part numbers and see if I can get you some clarification. My 91 makes some valve train noise, even with roller rockers. What brand were these rocker arms?
Customer: replied 4 years ago.

Hello They are OEM chev rockers they have a different tip on them kind of like a notch to keep the contact to valve running straight....

Ok, the correct part number should be 10089648 from GM. All 16 should be the same part number. There is no difference in intake or exhaust. Again, you will hear some valve train noise. Domestic or export should use the same rocker arm. I would just check on those rockers to determine if both part numbers are the same and those numbers are lot numbers or if they indeed are incorrect. From GM, the list price is $29 per rocker arm.
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