Iron head choices

[Rayzor]

During the rebuild of my 906 castings a crack was found. So they are junk now, but I have 2 other pairs to choose from.  A pair of 902 castings and a set of 452'S  from a motor home. From what I have read the flow of each is about the same, however the 452 castings have a few extra cooling passages around the spark plug area. Is this a benifit or something to be avoided. and if the 452 casting is prefered will I need a different type of head gasket .The plan is to stay with the stock intake valves and enlarge the exhaust to 1.81 size with hardened seats. I do not plan on doing any porting short of some slight blending in the exhaust as this is a mild build with an engle k54 cam. Thanks for any advice.

[firefighter3931]

During the rebuild of my 906 castings a crack was found. So they are junk now, but I have 2 other pairs to choose from.  A pair of 902 castings and a set of 452'S  from a motor home. From what I have read the flow of each is about the same, however the 452 castings have a few extra cooling passages around the spark plug area. Is this a benifit or something to be avoided. and if the 452 casting is prefered will I need a different type of head gasket .The plan is to stay with the stock intake valves and enlarge the exhaust to 1.81 size with hardened seats. I do not plan on doing any porting short of some slight blending in the exhaust as this is a mild build with an engle k54 cam. Thanks for any advice.

I would use the 452's and make sure you open up the bowl underneath the exhaust valve or there will be no advantage to using the larger valve. 

No special head gaskets for 452 heads.



Ron

[Rayzor]

What part of the exhaust bowl are you talking about. I know that when the larger seat is pressed in there is a lip that hangs over. But the bowl hog normaly takes that out. I was just planning on doing a little smoothing were the seat insert blends into the head. How close do I need to get to the valve seat to start the blend in. Oh also had the valves all back cut as I heard thats an easy flow increase. I would do more but I dont want to screw up my heads as I am not a porting kinda guy. I do have the mopar templates but have heard that they are not worth a damn and they are based on the 1.74 valve. 

[Challenger340]

I Vote the 452 castings as well.
See if the guy doing the exhaust seat enlargement has a 75 degree bowl cutter for his VGS, that he can apply after doing the 3 angle seat cut.
Make sure he puts the 75, so as to leave the 60 @ .125" wide.
For a street car, it'll make the Bowl blending much easier and simple.
You'll be able to "see" pretty easily, what needs to be "fixed" with a die grinder afterward at the edge of the 75. NO "edge", NO blend.

Bob out.

[Rayzor]

Thats the same bowl cutter he uses. Just after the cut towards the bottom of the bowl there are some small ridges that I like to blend away. at least there were on my last set. So the 452's even with the added cooling are the head of choice here. Any paticular reason why not to use the 902 castings. If they are not worth running then I will can them cause I do not need more junk layin around.