Quote:
Originally Posted by PRAY
I showed some results for my ported intake runner a bit back. I am still working on it some but with the low flow capability of my bench and flowing it on a 4" bore gains are hard to come by. I should have kept one of my valves stock (I do a custom 3 angle valve job on my valves) so I could do back to back testing. With my current weather situation over all flow is down but gains are up. I don't have an apples to apples for today but you can basically add 10cfm to the .3 and .4 number.
Today I worked on the exhaust port a bit. There is another 5-10cfm in the exhaust for sure. I had some spare time so I took a whack at it. The exhaust gains are really good but the port is overall down to my LS2/3/7 heads. This exhaust port is a unique critter for sure.
As soon as I finish up some LS2 heads I am doing I will take this LT1 head up to the local SF600 bench I use and get some 28" numbers against the stock ports.
The overall goal for these heads is to be a direct bolt on with the stock cam and gain 20rw over my numbers with my ported IM/TB, CAI and Headers. Swapping heads is easy and is really just a day job for the DIY'er. I will eventually match them with a cam line.
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Have you ever taken a look at the SAE paper GM published for the LT1 development? I had it around somewhere, it mainly talks about the trade offs they made to keep tumble and swirl up that sacrificed flow in areas for combustion efficiency.