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Looking to do the same thing to my manifold, since you've proven it works.
Curious how you removed the divider. Just roughed it out with a carbide burr from both sides?
Also curious about your head porting work. I figured the stock ports should produce some swirl, but apparently, they do not. 10 cfm is a nice gain though. Was that with a 3-angle valve job?
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I used a 6" length carbide burrs and worked it from both ends. I have this intake on my truck now. Road testing it I can pull a steep hill and still have power to accelerate up it. Before I would slow down. I'm planning on placing my truck on a chassic dyno to compare to the stock pull (stock carb, intake manifold, and breather).
First off I have not had the time to see what the results will be from this point on, life happens. All of the work that I have done so far was over a year ago. And I been wanting to get back to finishing it.
In the intake port valve pocket I reshaped the short radius, and some smoothing of the port. After a 3-angle valve job I made sure the transistion from the port to the bottom angle was smooth.
As far as the swirl, I had bolted my flow bench adapter onto the head and scribed the bore onto the head opposite side from the sparkplug. It basically convert the sharp edge (that shroud the intake valve) from the edge of the cylinder to the top of the combustion chamber into a ramp. Making a smooth transistion. The only major problem with this is it lower the compression ratio. There is two processes I will be performing to help bring the compression back up:
1.Cutting the head deck and the block deck. I believed the decks is thick enough not to cause an head gasket sealing problems. Will also need to make sure the block head bolt holes is fully tapped and clean to allow the bolts to go in without bottoming out.
2. Then I am going to offset grind the crankshaft from standard to .030" under to increase the stroke. Then mill the top of the piston to get the deck height back to zero, this will remove most of the dish from the top of the piston.
Both processes should raise the compression to approx. 9:1, hopefully or close to stock.
On another note: Doing the same thing on the exhaust valve (but on both side of the valve) will improve the exhaust flow by 15 cfm, with an open exhaust port. Not able to test this with the exhaust manifold bolted on because the flow bench is in the way.