[#73avenger]

Hello there, new member so excuse my mistakes and rambling. I have searched the net, read several books, and scoured this site, but cannot find what I am looking for. I am hoping there are some Dodge LA engine gurus who may be able to help me.
First I would like to know the combustion chamber volume of the J head. I have read 61cc,63-73.5cc and 68cc. (I would cc them myself but don't have any) Second, does anyone know of a photo on the net of where this J or X or O or U is? I have been told that it is easily seen on the pad between #s 1 and 3 plugs. From what I have read these J heads seem to be readily available yet the small block heads I have seen have nothing on this pad. (Perhaps they are too new?)
I am building a 360cid engine to race on oval tracks and the rules say 1.88 intake valves 1.60 exhaust. No X heads and 1.460 spring OD max with a single spring. Combustion chamber volume to be 70cc min. To my knowledge (which is humbly minimal on Mopar gear) the X and J are essentially the same head with possibly different valve sizes (so the plan is to run the J head with 1.88 valves if the c/c volume is greater than 70cc.)
Sorry about the length of the post, it seems to be getting a little long but I'm almost done.
I suppose what I really need to know is should I pursue finding a set of the elusive J heads or should I go with any old set of 360 heads? Again, from what I have learned on the net all of the 340/360 intake runner volumes are the same and I am restricted to 1.88 intake valves and 70cc heads anyway, so it seems to me the J head offers no advantage.
I am getting quite confused on this seemingly simple subject, can anyone help me out?