I have done it myself with the heads on with this: http://www.summitracing.com/parts/cca-5306
and a good set of ARP studs.
Remove rockers, clean head thoroughly, plug all holes, remove studs, tap, install studs one at a time, vacuum out shavings, blow it out, remove rags plugging holes, reinstall pushrods and rocker studs, adjust valves. Make sure pushrods are straight and rockers are good before reinstalling and be carefull about getting all shavings out.

 

Thanks LT1. Just got back from a test drive after tweaking the valve adjustment a little more. Seems to be running pretty good. I didn't push it hard cause I've got to get it up to the inspection station before anything else goes wrong.

63mako, I might give that a shot down the line a bit. Did you leave the heads on? If so, did you have any issues keeping your plugs from falling in? I know the one stud I replaced opened up into a water passage, don't know if they all do or not. Do any open up into the block or an oil galley? I've got a good vacuum, but I'd be afraid the plug would fall in.

It's funny, I had to loosen the valve adjustment a little more to get it to run right. Initially I went to zero lash and 1/2 turn, and it would barely start, did it again with 1/4, and it was better but still not good. I just went all the way around and set them at zero lash (cold) with no preload, I can spin the pushrods freely, and it runs like it did before the rocker went off the rails. Is it possible someone put a solid cam/lifters in here? The intake and carb has been changed, it has a Holley 4160 and an Edelbrock Performer RPM. The cam sounds slightly lumpy, but I don't know what an original L-46 sounds like. Or is it just that the hydraulic lifters are screwed up? Normally I would think of them failing to pump up when they go bad, can they "freeze" solid?

 

Actually now that I think of it, no way they're solids, way too quiet. But they sure like to be loose.

 

A sure sign of a hydraulic lifter is the appearance of a circlip or a wire clip in a three sided square - the purpose of the clip it to hold the pushrod cup in place in the hydraulic lifter. If it doesn't have a clip and appears to be a disk swedged into place, it is most likely a solid lifter.
With the pushrod removed and a good pencil beam light, one can actually see the top of the lifter to check it without removing the intake manifold.

 

Thanks, I'll give it a try after I get it inspected.