When it comes to heads, What's good for the 350 isn't necessarily good for the 283. This is a good article
https://www.onallcylinders.com/2018/...58cc%20chamber. I have a great results using the heads from the high output 305. Mine have a part # ending in 416 and there was another one from the 305's that was a good one too (ending in 601 I think). A good google search on "305 heads on a 283" will net you lots of reading. Bear in mind however, 305 heads were a light casting and have been known to crack when overheated. I feel they are worthwhile but one needs to take the care and time to have them checked out before installing them. Mine are rebuilt by my local machine shop and they got a good ol' port and polish job while they were there too. A street mannered 283 is never going to keep up with the "big boys " but they can be a peppy and efficient old school motor.