Swapping my 906 heads for 452's need some advice

[Sixt8Chrgr]

I need some help from the experts.

906 heads have broken valve cover fastener locations and I can't get the valve covers to seal. (mopar polished aluminum covers)
So I am considering bolting on a set of 452 heads that have been ported. The motor is a 68 383 4 bbl, mild cam, moderate compression, stock exhaust motor?  I know they will bolt right on but I was wondering about the compression ratio? Should I use certain head gaskets?

Thanks,

[71charger_fan]

http://www.moparmusclemagazine.com/techarticles/5115_cylinder_heads/index.html

[Chatt69chgr]

The 906 and 452 heads are both open chambered and I believe you will find that both are around 88cc chamber volume.  So the compression ratio wouldn't change assuming neither of the heads has been decked.  Even if they have, probably wouldn't change CR too much to worry about.  Plus, the 452's have hardened valve seats on the exhaust side.  Some say that if you run stainless steel valves this doesn't matter.  Porting doesn't affect the combustion chamber volume.  I am no expert so if I have misspoken I encourge the real experts to speak up.  I'm thinking that Fel Pro has some good head gaskets for that stock head.  Wouldn't you want to use the same head gasket thickness as before?

[Sixt8Chrgr]

Chatt69 thanks for the info. I dug around the internet and read some things and agree with what you say.

thanks again.