Polish not port my head

Performance mods and Advanced Stroker discussion.
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mticar1
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Polish not port my head

Post by mticar1 »

I'm building a 4.6 stroker, and I'm about to get started. I'm trying to do this as cheap as possible, and I want this jeep to run on pump gas, so I'm not looking for every last hp possible. I was planning on porting and polishing the head myself, but I found a shop that ships rebuilt heads. It would run me $362 for the head and 3 angle valve job and the basics, guaranteed not to be cracked warped etc..., anyway when I asked how much to port and polish, he said he wouldn't port it, but he would polish for free. I've done some research and I'm wondering how much will I gain by just polishing? I figure I can always port it myself afterwards and repolish those areas? Seems like a good price, its the 0630 head, and I'm planning to use the crane cam. I understand I will need to change the valve springs, but is there something I'm missing?
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Re: Polish not port my head

Post by Cheromaniac »

mticar1 wrote:how much will I gain by just polishing?
Performance-wise you'll gain 0hp, but polishing the combustion chambers will make the engine less detonation-prone so you'd have that as a side benefit.
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mticar1
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Re: Polish not port my head

Post by mticar1 »

I thought part of the reason to port and polish was to smooth out all the rough surfaces from casting that create turbulence inside the head? Either way, I can port the head and just repolish those areas? I don't think I could find a better price locally for a three angle valve job, cleaning, etc.., should I be concerned about ordering a remanufactured head?
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Re: Polish not port my head

Post by IH 392 »

Polished ports on a street engine are a total WASTE! of your $$, you'll not see any results from polished ports until about 7000RPM.
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Re: Polish not port my head

Post by FlyinRyan »

Polish the chamber, port the ports.
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Re: Polish not port my head

Post by SilverXJ »

Polish the chambers. If you want polish the exhaust ports and clean up the intake ports, but leave them rough. I wouldn't attempt a port job unless you have a flow bench to quantify the changes. Also, you might want to check the port alignment on the intake manifold runners to intake ports.
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Re: Polish not port my head

Post by akadeutsch »

!!!PORT ALIGNMENT!!! I had a 1/4" step going into my intake runner from my manifold before I fixed it. A step going into the exhaust runner is not supposed to hurt, in fact it is supposed to help stop reversion. So, leave the step going from the head to the exhaust header/manifold. But do your best to remove the step from the intake manifold to the head. Mine did not line up so good.
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