Is my 97 3400 LIM molded to clear non-roller rockers? PICS

[IsaacHayes]

Can anyone tell me if this 3400 LIM looks different than most?

It seems as though it's got more space for rocker to clear. No it's not machined like the 2000+ style, it's cast different. It looks flat compared to most others that look round buldging there.

Is this just my eyes playing tricks on me and every other 3400 looks cast like this? Or is it safe to say I may not need to grind much on this?

There isn't but maybe 1/8" of material where I'd be grinding. And pictures from other people (3100_modified) shows where they ground down really deep. I don't have that much material to go that deep! So I'm thinking this is a different cast shape.

In the picture I've only scratched a little and not taken much material off yet.

[Rhedalert]

I think they're all like that (the big port ones) I don't know why some are "shaved" by the factory, and some aren't (like yours)

[SappySE107]

That is how they look if they aren't machined a little from GM.

[IsaacHayes]

Hmm, ok. It looked like mine were flat, and others seemed more round and bulging. Like Brad's I ground on them some tonight anyways. I had more to work with than I thought. About a 1/4" and it took it down almost 1/8" or so.

One final question though:

When I put this on, and measure the clearance with a feeler gauge, and keep turning the engine over manually just a little at a time, check, repeat. What about the hydrualic lifters? Won't the lift be greater once the engine is running and thus my clearance dissapears right?

[SappySE107]

Use test springs to determine your clearances. I am not sure how much room you will need though. If you use the stock or stiffer springs, you will pump down the lifter some which will show more room than you will really have. Otherwise you could measure the amount the pushrod bleeds down. You only need to measure peak lift as far as I am aware.

[IsaacHayes]

Test springs? I'm not taking the heads or springs off the heads!! If I go that far I'll just put a 3400 or 3400 heads in.

How do I pump up the lifters with the engine apart?

bzopi and 3100_modified need to chime in!

I guess I could just grind the piss out of the manifolds until they are paper thin and then it should be good. I plan on grinding a little on the corner of the rockers too.

[bszopi]

Mine was easy to figure out... The rockers already did the work as to how much I needed to shave off.

[IsaacHayes]

yeah I'd like to not find out that way