Sorry I had put the wrong casting number. I'm pretty sure they are 346s and 516s. I know for a fact both are open chambered, and yes, I plan on using the KB280s
Oh and any pictures that you guys might have would be great.
The 516s are close chamber too. lol The open chamber heads are 906, 346 and 452. those are the most popular anyway....there may be more. the 915s and 516s are both close chamber though. But all the open chamber heads are pretty much identical.