need some help with selecting cylinder head Mopar 408

mopar_persson said
the pump gas i use is 98 octane
the cam is a P4120230 but when you order it the number is P4120231
http://www.summitracing.com/parts/dcc-4120231ac/overview/make/plymouth

(moper)
so i maybe need to change the pistons? :(
I have a pretty tight budget for the heads 2325 $ is the max i can afford right now.

$2325US? That's not bad.
Your 98 octane is the equilvilent of our 93. It's not that good...lol. The flat top pistons will make the static ratio too high, and honestly - that cam is too small to work with any pump fuel 4" stroker. What I would suggest is to modify your plans like this:
Replace the pistons with SRP dished - 16.5cc, D shape, set to be proud (above the deck) .005".
Run Out-of-the-box RPMs with the 63cc advertised chambers. They ar $1500 plus frieght, and all you'll need is to have the valve job checked and the springs replaced to match your camshaft. You will also need the ARP bolt package for them. I would think that will be close to $2300US in total.
Run the Fel Pro Performance .039 compressed head gaskets (recommended by Edelbrock).
Run a camshaft of at least 240° @ .050, preferrably something around 245° and lift around .530. Something like the XE284H or my perenial favorite the Crane H302-2 would do it for a hydraulic - or the solid MP P4120655 (although I'd consider any MP design to be the last possible choice... there's so much better out there.)

That's what I'd do.