i have a set of roller rockers off a I-gen block will they fit an LT1?

 

Lt1's need self aligning rockers IIRC. So no. Not unless you use guideplates on the LT1 heads.

 

but if i have guide plates the first gen rockers will work?

 

Yes but you may run into issue with the valve covers. I think the self aligning were also narrower?

 

Which rockers are they? What motor were they on before - one with centerbolt heads (same style valve cover as the LT1) or perimiter bolt valve covers?

Also, yes the LT1 does use self aligning rockers, so you'll need to use either self aligning roller rockers (they will have a 'lip' on either side of the roller tip where it contacts the valve so it can't slide off if it is a self-aligning rocker) or have guide plates installed under the rocker studs.

Aluminum head LT1s already have screw-in studs, so I'm not sure if they would need to be machined for guideplates, or if it would be ok to just stick them under the studs and leave the heads alone?

 

Not sure if the stock screw in rocker studs have enough threaded shank to let them use guide plates? Even if they aren't, a good set isn't that much anyways.

 

I've never taken a stud out of my LT1, so I couldn't say. But a good set of ARP studs is was around $60 last time I got a set. Good investment if you are using valve springs stiff enough to require roller rockers.