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By DualQuad312 - 10 Years Ago
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Hi All :-)
It,s been sometime since I, posted something on this Y-Block site. I, have a question on "Porting" It's been known for a long time that if a person cleans up the ports surfaces and ledges that Optimum flow can be achieved. With this being said is it just cleaning up the port holes so that there are No restrictions as the exh. air flow passes through? Or is making the holes in the ports of the exh. manifold larger and enlarging the exh. ports in the heads a significant gain in performance? Thank you in advance for your interest and your help :-)
Jeff
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By Ted - 10 Years Ago
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See if this link to an older thread helps. http://forums.y-blocksforever.com/FindPost46275.aspx
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By DualQuad312 - 10 Years Ago
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Hi Ted,
thanks for the reply. I, have a question though.....are the first two pictures of the exh. ports been ported or stock? I'm trying to do a comparison and use it as a gauge....
Jeff
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By Ted - 10 Years Ago
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DualQuad312 (5/2/2014)
Hi Ted, .....are the first two pictures of the exh. ports been ported or stock? I'm trying to do a comparison and use it as a gauge....
They are ported. I've also repaired the pair of links at the lower end of that previously linked page regarding the Cain manifold dyno testing. The latest software upgrade for the site seems to have made some of the older links inoperative and I've been having to modify them as I come across them to make them functional again.
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By DualQuad312 - 10 Years Ago
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Hi Ted,
thank you for clarifying that for me. Is it fair to say that I, should only be removing about a 1/16th of an inch on all sides of the ports, paying particular attention to the bottom hump area as to not grind very much in that area for fear of going into the water jacket? Thanks again fro the help. I, said a 1/16th might even be less in regards to the top and two sides of the ports. The bottom I, sure wouldn't want to do much to
Best regards,
Jeff
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By DualQuad312 - 10 Years Ago
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Hi Ted,
I, wanted to mention, back in the Fall I, was playing around with a pair of '56 Lincoln carbs. I, had converted them to Dual quads. I, did the conversions to match the original ECJ 9510's. Well anyway after a few attempts I, got the engine to perform pretty well. To the point where it performs as well as the ECJ's. what I , ended up having to do was to create larger booster rings to help cut down n the volume of air that the engine was trying to draw in. The ECJ's would typically use .750 diam. rings. I, ended up using .850's As I'm sure your well aware of Holley found it necessary to design a brass ring for the boosters in the primary circuit to help increase the airs velocity and also to help draw more fuel in for a proper air to fuel ratio. I, did some slight changes to the primary jets in reference to what you had suggested. #50's for the primarys ( it helped the engine not to run as Rich, the exhaust. was stinging my eyes at idle) I've stuck with the #82's for the secondaries. And I, replaced the stock #37 power valves and put in the original dual quad power valve #'s. #32's. Just wanted to let you know the arrangement does work and I, appreciate the help with it..... I, feel as though the bottom end has improved bottom end torque and equal top end speed as to the original ECJ 9510's. Note, I, should put the stock ECJ' s back on the engine at some point to confirm the comparison to the Lincolns ... LOl. thanks again
Jeff
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By Ted - 10 Years Ago
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Jeff. The List #1434/1437 Holley dual quad carbs with the brass rings do not incorporate the intermediate fuel circuits that are found in the single four barrel Ford, Mercury, and Lincoln Teapot carbs. When looking in the primary bores of the single four barrel Teapots, there are brass tubes aimed upwards at the discharge nozzles. It’s these tubes that help to draw additional fuel from the primary circuit at part throttle thus eliminating a potential dead spot or hesitation when running in the 1500-2500rpm range. The factory dual quad carbs did not use the intermediate circuits and instead relied on the increased signal from the reduced venturi opening with the brass rings to compensate for the removal of the brass tubes. On my end, if the manifold vacuum at part throttle is sufficient, then the brass rings have not been needed when modifying the single four barrel Teapots for dual quad use. What you’re doing sounds like good stuff though so keep at it.
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