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Discussion Starter #1
I am about to do a hc piston/cam install. Probably wiseco and CWR either 355 or 410 cams. My questoin is should I do any porting or pollishing on the heads? I have a full shop at work with every tool that I would need and the guy I work with used to own his own shop building drag bikes for over 20 years. I dont know if something mild like just polishing the heads would do me any good. I have a big gun full system, stock carbs, uni filter, and snorkels so I am not sure porting the heads would be bennifical. If it would be a good idea, what is the best way to do these heads as far as what to polish out and where. Let me know if i have blabbered on to much
 

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with shelf pistons, cams, stock carbs and especially snorkals i wouldnt bother.. now if you were going with better cams and pistons, bigger carbs and ditching the snorkals you would probably gain a little..
 

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Discussion Starter #3
That is what I was afraid of. I was thinking about going to a 3in pipe for the intake snorkel to get some of the air back. I feel once I do this rebuild, I will never get enough! So just doing some simple polishing of the intake and exhasut ports would not even yeild noticable gains?
 

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Better cams? Hell the CWR cams are just as good as any builder cam out there maybe better cause they wont flake like webs cams. Only issue with wiseco pistons is there not true compression. There 11.5:1 is only around 10.2:1. Find a used set of builder pistons and go with the CWR 418 cams (not 410) you will have one hell on a monster on your hands.

I wouldn't port unless you plan on going "BIG" BBK with 38-44mm carbs. The stock engine flows more then enough CFM to support a mild BBK.
 

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Discussion Starter #6
sorry I meant 418. G-rider, did you mean to say "would" or "would'nt"?
 

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"Wouldn't" you will gain nothing from porting your heads at this point.
 

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Discussion Starter #9
Thanks guys. I guess a simple polish of the ports wouldnt hurt nothing would it?
 

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Thanks guys. I guess a simple polish of the ports wouldnt hurt nothing would it?

DO NOT POLISH the ports!!!

polishes inlet ports actually take you backwards
reason: the polished surface, allows droplets to form on the port walls, and eventually messing with the a/f mixture

the way of thinking is leaving the ports rough after a porting job!!

however the exhaust port can still be polished!!

hope this helps
 

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Yup what he said. The intake port needs to be rough so it can mix the fuel and air together.
 

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The intake ports DO NOT have to be rough! If your fuel is traveling on the port walls, then the port is too big. Fuel suspension means the fuel travels mostly in the center of the port, suspended in the air.

If you look at all the winning heads in most major motorsports, they are CNC'd, and only a few I have seen over the years go back in , and polish them when they are done. Most leave the CNC finish.

Not that I have any opinion on it, but I have actually heard of test data stating that the cross marks left by polishing a port will aid in the tumbling effect, and further help support fuel suspension.

You don't want them to be mirror polished, as it is simply a waste of time. A 60 grit sanding roll, followed up with an 80 grit will do the trick.
 

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Discussion Starter #13
Thanks guys! This really shot down my long time thought that a port and polish job on any motor would help!
 
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