Heads? 452 or 906?

[Drakenman]

This is my delemia. I am wanting to port and polish a set of heads. Which one is best and why? I have heard a couple of good things about both and bads things as well. You tell me.

[Jims451]

Unported the "906" will flow slightly better than the "452" head. The "452" head had induction hardened exhaust valve seats for unleaded fuel.

If you port them they will probbly flow about the same. If you install the larger 2.14" / 1.81" valves you probbly have cut past the induction hardened seats of the 452 heads, so basically once you go to larger valves and porting they end up being pretty equal.

[Drakenman]

So you are saying that if i could get hardened seats for the 906 heads, then it would be more worth my time to get them ported and polished instead of the 452's?

[ehostler]

Unported, the 906s flow better than the 452s. After porting, the 452s will flow better than the 906s.

The 452s are also easier to get.

[beepbeepsrule]

My favorite head-porter likes the 452's because they have more "meat" on them and can be made to flow better than the 906's. His opinion, but I have seen his results and tend to believe anything he says!

[Drakenman]

Is there anyway that you can give me a name and number? I would love to call and talk to a pro about this stuff, not saying that you guys arnt pros! But a second opinion would be great. The thing is, is that i have a guy that will port and polish my heads for 300 dollars and bench flow before and after each port and do a three angle valve job, replace the seats if need be too.

[HEMI-DEMON]

Hey Drakenman, I've got the low down on this head situation, complments of Chuck Senatore at Muscle Motors. I don't know whose been lying to these guys, but the 906 casting is the best of the two, ported or not. The only advantage the 452 have is the induction hardened valve seats to run unleaded gas. If you keep the cam lift below .500" don't worry about the casting #s.
The 906 has the best floor of any production head and can flow the greatest amount of air at high lift, .650"+. Make sure this guy you've got in mind knows what he's doing before grinding on the floor of these heads, big numbers at high lifts will only come from pushing the floor back. Here is a number you can call to get futher assistance from the pros. 1-865-947-0426, Hensley Racing Ent. these guys know their stuff when it comes to building a engine. I hope some of this could help. I wouldn't let anyone touch my heads unless I was sure they knew what they were doing, anybody can buy a flow bench. Good luck.
If you are going to port these heads yourself, go with the 452's. it has a fairly flat floor that is easy to port and flows almost as well as the 906. The 452 seems to be more resistant to cracking in the area under the center two exhaust ports. I think you can buy porting templates from mopar performance, but gasket matching the intake port will have little effect on peformance if the lift is below .550". Once again, Good Luck and have fun with it.