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87IrocTim
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Joined: 10 Jan 2006
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PostPosted: Mon May 15, 2006 6:17 pm    Post subject: Reply with quote

i think it will be very practical and kick up my numbers quite nicely. that price does seem abnormally low, but shit im not complaining.
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artinla
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1971 Chevrolet Nova

PostPosted: Wed May 24, 2006 11:46 pm    Post subject: Reply with quote

I know that these aren't assembled, but this is also a great deal considering the CNC port work alone would normally cost this much. The flow numbers are pretty good.

http://cgi.ebay.com/ebaymotors/CNC-ALUMINUM-HEADS-CAMARO-SB-CHEVY-SBC-350-383-400-RP_W0QQcmdZViewItemQQcategoryZ33617QQitemZ8037883357
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Aerosmith
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PostPosted: Thu May 25, 2006 8:23 am    Post subject: Reply with quote

Just my opinion, but those $899 complete heads are waaay too small for what you have. Depending on your future plans, I would set 180cc as a bottom end and 215cc as a top if you are going to get serious. There are going to be proponents of alum vs iron and different opinions on port size and shape. do some reserch before you spend your money.
Pay attention to angle vs straight plug because some headers won't fit angled. On assembled heads make sure you know what you need as far as spring pressure, you will ruin your valve train with too much or too little pressure. Also check around (other bulletin boards) and ask about peoples experience with different brands of heads, just because it's "CNC'd" doesn't mean it is a good head..all cnc means is that someone ported a head and they used it as a model for a computer program to cut a million exact copies. You could cnc a turd, it wouldn't make it anymore than an exact copy of the parent turd.
Doesn't mean that it can't be good and inexpensive at the same time, just reserch before you buy. Chances are this will be the biggest single purchase you make for your engine, make it wisely.
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87IrocTim
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PostPosted: Thu May 25, 2006 1:41 pm    Post subject: Reply with quote

your exaclty right which is one of the reasons of why im here. I thought 160cc seemed a little small too but i would be still way improving what i am coming from. i would probably be most comfertable with 180cc runners. ill keep looking and asking around definitely, this will probalby be going down during fall and throughout the winter.
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artinla
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1971 Chevrolet Nova

PostPosted: Thu May 25, 2006 8:29 pm    Post subject: Reply with quote

For a 305, the 180's would be appropriate. For a 350 I agree that you might want to think about 190's or 200's.

As for the CNC'ed heads that I linked above, the flow numbers are good and I have personal experience with the pro-comp castings. I am not saying that they are the best, but they are pretty damn good for chinese (they say australian, I say BS) castings. However, if the porting was of no concern, I would buy the sportsman II's or a set of AFR 195's because they flow best out of the box with only slight massaging.
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87IrocTim
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PostPosted: Fri May 26, 2006 4:06 pm    Post subject: Reply with quote

my worries with the sportsman II's is because they are iron, if i got the 64cc chambers would i be risking some problems with compression? the car is strictly 93 gas because of issues with the new ethanol.
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af2
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1933 Willys Coupe

PostPosted: Fri May 26, 2006 5:19 pm    Post subject: Reply with quote

87IrocTim wrote:
my worries with the sportsman II's is because they are iron, if i got the 64cc chambers would i be risking some problems with compression? the car is strictly 93 gas because of issues with the new ethanol.


Yes you would unless you reduce the total timing. Those aluminum heads on Ebay would work just fine at 170cc"s. You go above 180 you will hate the low end. Those heads flow excellent for the port size. Remember the Vortecs everyone likes? Including me Have a 170cc runner but are cast iron. I had to change the total timing to 32* for the motor to be happy.
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87IrocTim
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PostPosted: Fri May 26, 2006 5:44 pm    Post subject: Reply with quote

im gonna have to take your word for it.
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af2
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1933 Willys Coupe

PostPosted: Fri May 26, 2006 6:43 pm    Post subject: Reply with quote

87IrocTim wrote:
im gonna have to take your word for it.



All I have to say to the big Port guys is I wish those heads were available when I built the Jeep Shocked Could have got a head that flowed better than the Vortecs I bought and be Aluminum Evil or Very Mad
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SMOKEmUP
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1979 Chevrolet Camaro

PostPosted: Fri May 26, 2006 11:13 pm    Post subject: Reply with quote

The larger volume, the bigger cross sectional area of the cylinder head. The bigger the cross sectional area the slower the velocity. The goal is try to optimize the velocity to point where the volumetric efficiency peaks. This is usually around 0.6 mach.
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