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By grovedawg - 13 Years Ago
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I have been building this motor for a LONG time now- almost a year. It's a 292 bored out to .030" over 312, or 3.830" bore. I had a local shop offset grind a 312 crank to a 3.610" stroke. I had the journals turned down to utlize the Eagle Forged Feather-weight H beam connecting rods, 6.125" long. I also bought a set of custom forged aluminum flat topped pistons that John Mummert offers (Probe). I also chose a Mummert cam Y-284S, with 236 duration at .050", with 108 degrees separation. I'm running stock 312 rockers with a 1.54 ratio, and Comp Cams dual spring 985-17 (A little stiff for my application). I had a torque plate made up and for honing the block (Steve Flatt is my machinist). My combustion chamber is 66cc, and the piston comes out of the hole .006" for a quench of .038". Compression ratio is right at 10.2:1. I also followed Tim McMasters guidelines on pressurizing the rocker arms. With some instruction from John Mummert I also ported the heads, and they flowed surprisingly well, 225 on the intake and 165 on the exhaust. Dick York (Dickster) worked his mojo on my tri-power set up, and Frank Quinlin’s Dyno Shop in Nampa ID helped me break her in. HUGE THANKS to everyone I’ve bothered along the way, including John Mummert, Tim McMaster, Ted Eaton, and everyone else on the forum who has answered questions and offered parts/advice along the way. Enough said, here's the video and the dyno sheet.
Start Up Video at YouTube.com
Dyno Pull at YouTube.com
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By glrbird - 13 Years Ago
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Dawg How long did you hold your breath on the start up? Should make a great street engine. Now you have to finish the truck. Isn't it great when everything comes together in a good way!
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By MoonShadow - 13 Years Ago
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Great sound! I love the smell of a new Y-Block in the morning. Chuck in NH
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By Rono - 13 Years Ago
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Grovedawg; CONGRATS on finishing your motor project. She sounds GREAT! I lived in Boise for 20 years and I'm happy to see another Idaho guy finish his pet project. I used Performance Soultions on State Street for the dyno testing on my last motor. Hopefully I'll finish my 331 blown Y-Block within the next year and will be able to post my dyno run too. Good Job! rono
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By YellowWing - 13 Years Ago
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Nice job! Sounds great and pulls very well. Bet you can't wait to get everything done and take it for a ride.
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By grovedawg - 13 Years Ago
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I'm all jacked up to get her in the truck. I listen to that video EVERY day. 
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By mctim64 - 13 Years Ago
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Sounds great! How about your carb problem, what was it?
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By grovedawg - 13 Years Ago
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Jetting was WAY OFF. I started with a 51 main jet, and 49 jets on the secondary. I ended up with 64's on the mains, and 66's on the secondaries. She's a little rich for my altitude, but I won't have to worry about re-jetting if I drive to the coast.
Thanks for your help Tim!
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By 569104 - 13 Years Ago
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Grovedawg, Sounds fantastic! Great job. Have you got it in the truck yet and taken it for a drive?
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By grovedawg - 13 Years Ago
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No. I keep adding things to the list as I go with completing my truck. What started out as a "strip-down-to-metal-and-repair-and-repaint" has slowly turned into a very custom little truck. So, I hope to have all the body work and paint done by the end of the summer. Maybe I'll be able to drive her out of the garage under her own power early fall. Keep your fingers crossed. 
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