Your best bet is to get one for a 2.3L mustang and have an adapter machined. Worked really well for me. as for rockers, I believe only 1 was ever made for chevettes. no one makes after market.
I was looking at the 2.3L ford lifters, and they look extremly close in size, and may be on option for off the shelf solid lifter. I havent got my hands on one to accually compare