Help with 340 compression + cam change

AJ and wyrmrider, I've read your posts several times.

wyrmrider, I hear you saying to forget the 1.6 roller rockers to boost lift. Is this primarily due to cost/effect? Without any real experience it "seems" like they would boost lift #s while keeping pretty much the same duration. I am fine with my 273 rockers, but trying to understand.

AJ, I appreciate your analysis! I have long known it wasn't doing what it should. (I have the old Mopar bibles and have seen the charts on W/P and build levels and what it should do, even by the old standards.)
I do get a little confused here, I'll admit. I know it's all in the balance of parts, but I think you are saying you yourself would start with getting higher compression pistons in the motor, ...but also if just changing cams, saying that more cylinder pressure (XE275HL) with iron open chamber heads could possibly be too much without retarding the cam some. With closed chamber heads/good quench I understand how higher compression can work. Not sure what happens with higher compression and the X/J heads. Is it that with higher compression the efficiency goes up, and a bigger cam can work better as it bleeds off some of the compression at the right time?

I know I am resisting the idea of tearing it all apart for a number of reasons. Cost, and down-time, of course, but also that it is in such good condition and done with high quality parts etc. and I hate to mess with it if it's running well. So I either rethink things and consider a rebuild, or I am stuck with the "cam or no cam change" question.

Also I like a challenge, so wyrmrider (and others) when you say "8.5 motors can be made to run well" I am trying to figure out what that takes.


By the way, here are the specific cam recommendations I got:

Mike Jones-
280/280, 224/224 @ .050, with .495"/.495" and 108 LC, plus he recommended limited travel lifters.

Howards-
267/267, 220/220 @ .050, with .506"/.506" also at 108 LC.

Dwayne Porter was a bit more conservative saying maybe an XE 262 or Voodoo 701 or 702 at most, but suggesting I might think about getting different heads that would actually work much better for my purposes than the ones I have.