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Discussion Starter · #1 ·
I'd really like to know if anyone has done a comparison or made measurements using roller fulcrum rockers to decide whether or not they're 1.5, or 1.6:1 ratio. I've searched and read "definitely" and "probably" and "depends on the year." I have zero experience with 3400 internals, and I've only stripped a handful of 3100 engines, so I am not familiar enough with the valvetrain configurations to point out specific changes.

I have 16 rockers here from an earlier 3100 engine and as far as I could tell from measuring pushrod seat center to fulcrum center, and fulcrum center to valve stem wear point, they were only 1.5:1. I also know the later 2200 OHV engine was reported to have 1.6:1 rockers by GM but it turns out they're actually 1.5:1 as measured by an aftermarket vendor. The only 1.6:1 rockers installed by GM that I know of are the LT4 rollers made by Crane and those ain't cheap. I'd love to be able to find some inexpensive 1.6 rockers which have roller fulcrums. And by inexpensive, I'm talking about going to the local boneyard and spending less than $20 on 'em.

Thanks.
 

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The roller fulcrum genIII rockers are 1.6.

It's the early stamped steel rockers from the 3100 that there is some debate on.
 
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