340 Max HP Potential with X/J heads?

fishmens67 said
and plenty have screwed them up.

moparodbuster said
From what I gather, the 915 J's aren't going to flow much different than the eddys once ported so I've gone ahead and bought them for $300. They are untouched from factory from a 71 360. Im in Australia and there aren't any machine shops that are familiar with what I need to do to them now to get them to their 90% potential so I need specifics to tell my machinist exactly what to do to them. Thanks for the help! I'll post a new thread with this question to maybe get some different ideas.

To the op.
If you don't have the skills or tools to port your heads. Just ask your machinist to do a good 3 angle valve job. when you get them home, remove the intake valve and smooth up the bottom cut in the throat. This is the single biggest JUMP in CFM that you will get in porting the head.
Yes there is a lot more HP potential hiding in them heads but it take a lot of time and patience to get out of them.

From that point i would jump to the iron RHS heads.
or if you must eddies that need to be sent to you machinist to have some clean up done for longevity.......
Just my .02 sence