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Ill port them myself. Now I have practiced porting on heads for endless hours but what I still dont get is how Im supposed to tell if I made all the runners the same. I mean its very possible that by doing it myself that when Im done none of them will be the same. Does it matter if one flows just a little differently than others and so on?????
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All the intake ports on the manifold are different. BBC intake ports are all different. They run. Last edited by F-BIRD'88; 01-05-2013 at 06:14 AM. |
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Tip: a rat tail file helps you straighten up the corners
A hand flat metal file helps you keep the walls straight and smooth your carbide progress. if you stick to it and do a good job those heads will turn out very well. Just pretend they are camel back heads. |
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As I suggested in another post why you would best suited to build a home flow bench first.Flying blind is returning to caveman tech of all too many yrs ago. Any suggestion that is doesn't matter,the source doesn't have enough practical experience.
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Or another way of looking at it is the same theory behind using non equal length headers- they will tend to lower- but BROADEN- the powerband. Same thing w/ports that are not exactly the same. And w/production iron heads, there's a LOT of room for improvement, regardless if the ports are identical or not.
But w/novices I will always recommend have the guides done, and an accurate 3-angle valve job, and back cut the valves if they have the ability or a few extra dollars in the budget. Then at home stick to the low-hanging fruit: do the bowls, clean the flash and port match the intake (NOT gasket match!) and match the headers and gaskets to the exhaust ports. Leave the short side alone. Do not reshape anything. Leave the valve size stock 1.94" x 1.5". Otherwise, spend the money on a set of aftermarket heads. |
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Fully port the intake and exhaust ports. Yes smooth and blend the short side radius.
Yes smooth and steamline the vavle guide boss to create two strong flow paths around the guide boss. Do not fuss over wether the ports vary in flow by 1 or 2 cfm. just make them visually as close as you can. The critical part that matters is the size of the push rod pinch area. create a guage to check sizes. Good result can be had with the stock valves. But on these head once fully ported a 2.02x 1.60 valve or a 2.05x 1.60 valve set works very very well. These headss need generous porting for good results. But use a felpro 1205 gasket as a guide. Again do not fuss over minor variation in port flow. This BS advice is from people who have never ported a cylinder head or actual built high performance engines. How did we all create powerfull race engines before CNC porting and the internet? These heads are capable of 260+cfm when fully ported with a 2.05" valve. You can hit about 240cfm with a 1.94" valve. which is a big gain from 198cfm stock.. 1-2-3 cfm don't mean squat. Don;t be shy with the porting and do not listen to amateurs. Racers have been sucessfully hand porting stock SBC cylinder heads and getting big air flow and horsepower gains without CNC machines or flow benchs, since 1955. I have been doing this for 35+ years. Long before CNC porting. You can too. |
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A full good home brewed porting effort and 2.02x 1.60 valves creates a strong high performance cylinder head
from these stock chevy cast TPI heads. Capable of 400+HP. Short of the vortec (062-906) and aluminum ZZ4 // TPI cousin heads (113) These are the 3rd best late head GM made. They end up equal or better than the old Camel back heads when equally fully ported. A small half effort will get you a small half result. |
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Here is a picture of the 083 "TPI head" in full ported form with big valves.
http://www.hotrodders.com/forum/atta...0&d=1347916622 You don't get this by just going for the low hanging fruit. The meat and potatoes is deep in the port. |
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Reported to forum management.
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That it takes time and experience to get it right and verification with a flow bench through trial and error. If you truly want to take it to the next level,do a search to start learning more.It is useless for you to have to go through the same things we did from the 50's to the 90's and then call it all good. Maybe what bugs me the most,is a suggestion you ignore all during that time what we learned. That is maybe the single most important thing that has made such a huge difference from the very old school way of doing things. |
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I have done all the flow bench research already for you and am passing along the knowledge
I personally gained by hand porting many sets of SBC cylinder heads. Both stock OEM castings and aftermarket. Get in there and get busy. Don't be shy. You will get good results and make a lot lot more power than stock. |
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Telling people w/o any experience to alter the short side radius is just wrong IMO. You seem to think that no harm can be done to a cylinder head regardless of how much is hacked out of it. You (should) know better.
If you were "passing out" anything of real value other than green lighting hogging hell out of a head, then you'd send each of these people templates that could be duplicated in brass, of all the important radii/sections of the ports. In this case, I don't even see good photos- which leave a lot open to interpretation even if there were a hundred of them. |
| The Following User Says Thank You to cobalt327 For This Useful Post: | ||
1Gary (01-06-2013) | ||
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