Gen 6 push rod length

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08-10-2007, 12:49 PM

69-CHVL

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Gen 6 push rod length

Have any of you guys experienced the need for really short push rods in these motors? I have a 454HO shortblock and ZZ502 heads. I did deck the block .020. But the contact pattern I'm getting is way outside on the valvestem, but the pattern is narrow.

Your thoughts?

08-10-2007, 02:25 PM

kennyo

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I had to go to custom length P Rods to get my pattern right when I went to roller rockers.

08-13-2007, 10:34 AM

lilredboat

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i had to measure and get custom lengths when I went to new headsand roller rockers on my gen VI as well.

08-13-2007, 12:43 PM

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Deck / head milling / and or headgasket thickness change will also (in additon to other valvetrain changes) change required pushrod length.

Non-adjustable BBC's valvetrains use different pushrod lengths than adjustable. Then add to the fact roller vs flat tappet use different lengths.

Example: OE GM:
8.285" intake, 9.256" exhaust pushrods used on OE Mark IV flat tappets. 7.575" intake, 8.525" exhaust used on OE 454HO and 502 engines with rollers.