Contour Enthusiasts Group Archives Forums Modifications 3.0L Duratec About the heads

Hello guys! let me get this straight on the heads of the 3.0liter conversion:

I can use the non SVT heads without trouble, and the compression ratio would rise a little above 11:1. However, it is highly recomended to change the intake/exhaust valves for the 3 liter ones on non SVt and SVT heads for proper flow since the increased displasment

Right?

BTW, can I use the same timming chains?


Thank you very much!

you are correct to a degree. IIRC, nothing needs to be done to the heads, but the block there are two oil return passages for the 3.0L heads that need filled that our 2.5L heads do not have.

Originally posted by Joaquin:

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Hello guys! let me get this straight on the heads of the 3.0liter conversion:

I can use the non SVT heads without trouble, and the compression ratio would rise a little above 11:1. However, it is highly recomended to change the intake/exhaust valves for the 3 liter ones on non SVt and SVT heads for proper flow since the increased displasment

Right?

BTW, can I use the same timming chains?


Thank you very much!

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No, just putting 3L valves in won't help you at all. You need to get the intake valve seats cut for the 3L valves, and new exhaust valve seats put in for the 3L valves, a 3-angle valve job, and port the intake/exhaust passages to compensate the bigger valves. It takes time and money, but it's well worth it.

It also takes mor combustion chamber work to unshroud the valves properly. Flow numbers indicate that without the chamber work, P&P heads with the stock 2.5 valves can out flow the larger valves without chamber work done on 2.5 heads...