anyone have real proof that 98 heads flow so much worse than 99 up heads....??
12-06-2007, 09:46 PM
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anyone have real proof that 98 heads flow so much worse than 99 up heads....?? lookin for real flowbench proof that the 98 heads are as crappy as everyone lets on.....i know the deal about the casting but have yet to see any proof./....
12-07-2007, 02:54 AM
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there's a site somewhere that has all these flow numbers. I forgot where it's at but do a search, I found it posted on here somewhere. But if I remember right pretty much all the LS1 heads flowed the same, it didn't really change till the LS6 heads came out. The numbers were pretty low though compared to ported heads obviously.
12-07-2007, 03:00 PM
#4
They shouldn't show any lower numbers unless they were inconsistantly ported. The only difference between the two is the way they are cast that leaves the 98 runners slightly more textured. Porting a early 806 head should be no different than porting a 241 head.
12-07-2007, 03:08 PM
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853 heads were cast differently than the 241 heads - the 241 heads flowed slightly better becuase of the better casting method. i've heard they dyno and average of 5-7 rwhp better than the 853 heads.
if the heads are ported there will be no difference.
however, there is a difference between the ls6 heads (243 casting) and those ported, will see slightly better results than ported 853 or 241 castings.
if the heads are ported there will be no difference.
however, there is a difference between the ls6 heads (243 casting) and those ported, will see slightly better results than ported 853 or 241 castings.
12-07-2007, 06:44 PM
#6
853 heads were cast differently than the 241 heads - the 241 heads flowed slightly better becuase of the better casting method. i've heard they dyno and average of 5-7 rwhp better than the 853 heads.
if the heads are ported there will be no difference.
however, there is a difference between the ls6 heads (243 casting) and those ported, will see slightly better results than ported 853 or 241 castings.
if the heads are ported there will be no difference.
however, there is a difference between the ls6 heads (243 casting) and those ported, will see slightly better results than ported 853 or 241 castings.
12-07-2007, 07:02 PM
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To really know if they flow worse we would need to flow 10-20 of each casting, to get data that means anything. With core shift and manufacturing differences, the same castings could flow different. I doubt anyone has done that. Some people say that because the don't look as nice finish, but those are people who do not understand airflow. I would say with the early casting the chance of betting a less flow number head may be higher, I doubt it would amount to much on the track! Also, don't forget the highest flow numbers will not always make the best power!
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12-08-2007, 06:44 AM
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To really know if they flow worse we would need to flow 10-20 of each casting, to get data that means anything. With core shift and manufacturing differences, the same castings could flow different. I doubt anyone has done that. Some people say that because the don't look as nice finish, but those are people who do not understand airflow. I would say with the early casting the chance of betting a less flow number head may be higher, I doubt it would amount to much on the track! Also, don't forget the highest flow numbers will not always make the best power!
I've always been skeptical of the differences and whether they would really show up on a street car. IMO it's just another excuse to show that `98 cars are inferior. Which they are not, their just different.
An LS1 is an LS1 just be glad you have one.
12-11-2007, 09:24 PM
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thanks guys ive searched and all i found was the runner size valves and the casting texture....i was in a debate with some kids on another board ....i dont think they will show any differences on the street or track iether....
12-11-2007, 11:57 PM
#11
i would think that the 806 wouldnt flow *** good as the 853 cuz it was a newer disign like the 241 flows better than the 853 and so on with 243 vs 241
so a 806 probably isnt much diff. than 853
but the 806 vs the 243 would have a large diff.
just my guess tho
so a 806 probably isnt much diff. than 853
but the 806 vs the 243 would have a large diff.
just my guess tho
12-12-2007, 05:10 AM
#12
When, I decided to port my own heads years ago, I had the front and back port flowed on my 98 heads. This was years ago and I forget exact numbers. But remember, all benches are different, operators are different, but all my numbers were on the same bench, same operator, just different time.
Stock 98 ports were in the 225cfm range. I cleaned them up and they were in the 250 range. When I was getting them milled, the stone broke in the milling machine and the machinist ordered me a new head about 30 minutes before he called me and said he had taken care of it. When I picked up the heads, I had one center bolt head. He had ordered the wrong one. He had already milled it so he couldn't send it back. He ordered my correct head and let me keep the wrong one as well. We flowed that one as well. Only front and back port. All 4 ports were between 4 and 6 cfm of each other with the 98 head a little behind in flow. However, I ported the newer cleaned up the newer head in the same manner as I did the older ones and flow was within 5cfm between all 3 heads. None averaged any better than the other as I'm convinced the difference was in my hand. I'm not a pro porter, I'm not even and amature, I picked up a grinder and wanted to see what I could do and I was kinda impressed. Don't have the data anymore but that's how I remember it. I do still have the heads in my basement though, If I can find the valves, maybe I could look up some old friends and have these things flowed again.
Stock 98 ports were in the 225cfm range. I cleaned them up and they were in the 250 range. When I was getting them milled, the stone broke in the milling machine and the machinist ordered me a new head about 30 minutes before he called me and said he had taken care of it. When I picked up the heads, I had one center bolt head. He had ordered the wrong one. He had already milled it so he couldn't send it back. He ordered my correct head and let me keep the wrong one as well. We flowed that one as well. Only front and back port. All 4 ports were between 4 and 6 cfm of each other with the 98 head a little behind in flow. However, I ported the newer cleaned up the newer head in the same manner as I did the older ones and flow was within 5cfm between all 3 heads. None averaged any better than the other as I'm convinced the difference was in my hand. I'm not a pro porter, I'm not even and amature, I picked up a grinder and wanted to see what I could do and I was kinda impressed. Don't have the data anymore but that's how I remember it. I do still have the heads in my basement though, If I can find the valves, maybe I could look up some old friends and have these things flowed again.
