Originally posted by 3400-95-Modified
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Yes, the '02 engine definitely has the larger valve guides. It started in late '00.
He may actually be getting some valve float too. Most grand ams I've seen dyno'd power falls off 400-500rpm before the stock redline, and since he has a DHP pcm his redline is higher than stock. I got it on good confidence from a certain GM engineer we talked to at one of the grand am picnics in lansing that the stock LA1 valve springs were known to start having valve float issues before the stock redline after they get some miles on them. Probably why they upped the spring rate on the 3500, and the reason many of us started swapping in LS1 springs for stock cammed cars to begin with.
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