Federal Mogul still has lifters for the hydraulic 235 and 261's. The Part number is HT-761. They're extremely expensive though, somewhere around $20-$25 each. As far as the cam goes, you'll either have to have yours reground or have a new one ground. Again, more $$$.

They best value would be to go with an OE solid cam. Federal Mogul has new solid cams and lifters availible. You can pick up a cam from Patrick's or Rockauto for a little over $100 and the lifters about $10 each. The part numbers for them are: Cam-CS-293, and AT-874 lifters, the low lift solid cam is CS-251.

Chris