have 455 engine. decked .030 how or what should i do to determine correct pushrod length. hydralic lifters. or do i just shim the valve springs and leave pushrods and rocker stands alone.thanksbill

Asked by Apr 05, 2008 at 05:48 PM about the 1968 Oldsmobile 442

Question type: Car Customization

2 Answers


You should be able to use stock pushrods. I would not shim anything until I could determine that there was an issue. The .030 over boring shouldn't affect the pushrod length.


well getting your block decked .030 and I am assuming you are rebuilding the engine, you will have new head gaskets, and depending on the thickness of the gasket, it will also vary your pushrod length. Go to comp cam, and they have a pushrod length checking tool. You set it up with your valve springs and rockers that you are going to use in the final build to check for your zero lash. Do not shim the valve springs, because that way, you will take off the valve pressure on your heads, that isn't good. Leave all those things alone. Buying a set of correct pushrods is much cheaper than going in trying to work things around the pushrods. It doesn't make sense to work your rockers, springs and lifter set up around some pushrods. You would raise the compression on your engine having your engine decked. What all are you trying to get out of it. A stock 455 have a 10.1:1 compression, and anything higher, you would want to start mixing race fuel in your fuel to get the correct combustion. What all are you looking to get out of the engine, and what all are you doing to it? Goodluck

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