what is the max lift u can have before the rocker hits the stock valve cover? before removing the baffles, its on a 91 305 thanx if u can help out

 

I haven't found the baffles to a be a restriction to lift. Clearance problems ususally crop up with fat aluminum roller rockers, and that's a side-to-side thing, not really a lift-related problem. The Crane Gold narrow rockers will clear without a problem and are available in self-aligning style, but are pricey. For applications where I've converted over to guideplates I find that I can make less expensive Harland Sharp rockers fit if I squeeze the stock oil baffle box JUST A SMIDGE with some pliers, some patience and trial-fitting.

If you have stock length pushrods in the motor the next thing that will limit lift will be the backs of the rocker arms hitting the inside of the valve cover. And that's not something you need to worry about until you are lifting the valves a LONG way, with most sets of rocker arms. Stock ones will never hit. Harland Sharps I have gone as high as .560" and never hit. Crane Gold rockers have a little "lip" on the back of them that will limit lift, but I still haven't found their limit, either.

 

dam u seam to know ur stuff i have my 305 and i got a set of vortec heads that i want to put on it and was looking at going to 1.6 rockers which would put my lift at 490 with my lt1 cam i got, now can i reuse my stock pushrods or? not sure on this part, i will be getting the heads milled to keep my stock compression at either .020 with that 1094 .015 gasket or .045 and get the intake done to match up again, thanx

 

On my set up I'm running Trickflow heads with .528 lift on 1.6 RR's and the stock rocker covers with no problems. By there were no modifications to the factory covers. Allen

 

A buddy of mine is running .550 with the stock centerbolt covers with no problems.

 

It's generally not the rocker body itself that creates any up-down clearance issues with any rocker arm. Rather, it's the use of the poly locks.

 

I think this is true for the most part. Definitely not the part of the rocker that pushes down on the valve as it goes down. The only part that MAY hit is the back of the rocker pushed up by the pushrod...and as you say, it generally doesn't get as high as the poly lock itself.

 

Running Vortecs with stock studs, then ARP studs, 1.5 Comp Pro Magnum Full Roller Rockers (super fat bodies) with stock centerbolt valve covers, .454 @ 50 max lift.

Poly locks aren't an issue on my setup, and ones where they WERE an issue, I was able to remove most of the wrench flats at the top of the poly lock (no need to be able to put a lot of force on them) to clear. The poly lock sets I've used all seat the set screw WAY down in the poly lock, so removing material up top doesn't hurt a thing.

The problem I did have was the width of the rockers, but that is/was EASILY fixed by removing just the very bottom of the support that holds the post for the bolt hole. The factory bent it over, that is what didn't clear the rocker body, and only one half of that support, not the whole length, since the thickness is the trunnion, and thats it. http://dyeager535.topcities.com/vortec.html

 

Usually the amount you mill off the head will not make that much difference in the length of pushrod required. Typically, the head is milled down some but you still use a rather thick rebuilder gasket- .039", so it's a wash. Even if you used a thin gasket (~.020") we're talking about a negligible difference. Especially since milling and thin gaskets make the stock sticks act effectively "longer" than they would otherwise. Little too long is usually not a problem.

To give you a point of reference, I check all my engines for optimal pushrod length. I don't even bother buying different length sticks unless I'm off by .050" or more.