open chamber heads question

[leanburn]

i was talking with my engine builder and he's telling me that the heads i have are far from ideal for my stroker build. they are the 65cc open chamber for the 340's. he suggested that if i want to use these heads that i should use a kb hyper piston that comes above deck so that i get the proper quench but i would be 9.5:1 compression. is there any other options out there for pistons ? should i ditch these heads?

[Rob C]

65 cc is considered closed. What size engine is this?

[Chryco Psycho]

I would avoid the Hyper pistons , use a forged instead
Which head do you have , the later 88-92 308 heads seem to make the best power

[Aussie Challenger]

Depends upon what size you are going to take the motor too and what you expect from it, if only a mild build the 340 head with a clean up will work, as C.P. recommended the 308 is a better option with a clean up or some serious work, depends upon how much you want to spend.   

[leanburn]

sorry guys i forgot to mention, the heads are the eddy rpm. i'm looking for 500 hp out of a 408.

[Chryco Psycho]

if you want some serious power the latest W2 heads are awesome but expensive by the time you get all the parts to go with them

[moper]

The heads you have are the 340 versions, which have the full chamber machined into them. They are supposed to be 2ccs larger but I think they might be a little more than that if you measure. The biggest issue you will have is keeping it pump fuel and making the number. You can do it, but you are starting off a little hobbled by the deeper chamber. I like using hyper pistons, but they have no business in a stroker engine of any kind. Forged is the only way to go due to piston speeds. What I would suggest is if you need to use them, have the heads milled to make them closed again. Just be aware they will end up closer to 60ccs. To get 500hp, you'll need to work the heads anyway so milling shouldnt be a stretch. Then you can use a real piston, and if it were me, I'd use a dish and run it to within .030 of the head. Tight quench means more static ratio and better output with pump fuel.