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Here is some more info if you want to read up more. I agree the number seem low, How ever you need to know what a stock un modified port plows on that specific bench with that bore size to get an Idea of the improvements you made. Its just like a dyno.
His discussion on how the bottom of the intake port, where the velocity is HALF of what it is at the highest point of the intake port-closest to where the injector is spraying, is quite note worthy. Further, the castings that he did of the intake port show exactly why a "raised runner" intake port would probably flow significantly better. If only... If only he had flowed an all stock intake port with a raised/epoxied floor... I would pay good money to see what the differences are between an all stock port, and a stock port that simply had the floor raised with epoxy and NO OTHER CHANGES so you could really see what that one change would make. This is why I should buy a flow bench and then we (the Ls1 tech community) could run all types of crazy tests! Then... you have to wonder if you had a raised runner intake port... and a matching intake manifold... what great LS goodness could come from that?
I thought the smaller bore would flow less, but I wanted more realistic numbers for the 5.3L bore. Maybe my ported 706 heads would have beat some of the stock 243/317 flow numbers with a bigger bore. It definitely would have been closer with a bigger valve. Maybe next time I port and flow a 706 head, I'll have it done with a 4" bore. That would be interesting.
I have an extra set of 706 heads in the tool shed. I have been thinking about finishing them, and putting them on my Camaro. Everyone says the 317 heads are the worst for my LS1, but they do flow good. They were also milled, so the compression is still stock. I could steal the valves from the 317s, and drop them in the 706s. My ported 706 exhaust ports flow about the same as the ported 317 exhaust. The intake flow numbers are way off though. Maybe the bigger valve and a bore would get them closer...? I need to finish putting the 5.3L together before I start another project.
Save the 706 head idea and bigger valve for another day for a 6.0 lq4 block....
that's work or porting on free time and time to gather all your ideas on what direction the work is going. You can pretty much know the CSA of the head with the CC ...
Bigger Valve with a bigger 4.00 bore will Always show more than the 5.3 bore. Same head being tested.
His discussion on how the bottom of the intake port, where the velocity is HALF of what it is at the highest point of the intake port-closest to where the injector is spraying, is quite note worthy. Further, the castings that he did of the intake port show exactly why a "raised runner" intake port would probably flow significantly better. If only... If only he had flowed an all stock intake port with a raised/epoxied floor... I would pay good money to see what the differences are between an all stock port, and a stock port that simply had the floor raised with epoxy and NO OTHER CHANGES so you could really see what that one change would make. This is why I should buy a flow bench and then we (the Ls1 tech community) could run all types of crazy tests! Then... you have to wonder if you had a raised runner intake port... and a matching intake manifold... what great LS goodness could come from that?
What do you mean Eric W... did that on YouTube months ago.
Difference your talking about in Raised runners?
Ls1 vs Ls3 vs Ls7 vs Lsx Dr
The 243 exhaust ports look bigger than Eric Weingartner's LS3 epoxied intake lol. I worked the exhaust to mate to the exhaust manifolds on my Camaro. Sometimes you just have to say screw the raise the roof stuff and make it work for your ride.
The 243 exhaust ports look bigger than Eric Weingartner's LS3 epoxied intake lol. I worked the exhaust to mate to the exhaust manifolds on my Camaro. Sometimes you just have to say screw the raise the roof stuff and make it work for your ride.
Here are a set of 706 heads I did some basic porting to. The intake valves were enlarged to 2.00 and the throat was adjusted to 90% and blended into the bowl. The exhaust is stock valve size. Basically a good cleanup on the exhaust. I did make the exhaust guides more aerodynamic and raised the roof a tad. This was also flowed on a 4.00 bore with no pipe. Biggest difference compared to yours is the .300 exhaust number and of course the intake flows.
Another good head porter to check out is Charles Servidio's Youtube channel since he includes air speeds in his stuff. Air speeds seem to be the key to making a cylinder head flow well.
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