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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: lukieg on December 14, 2011, 09:23:05 pm
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Im going to swap out the 366 for a stock lg4.. I need a daily driver.. got a great deal.. come get it and shes yours. Im not spending any cash.. or at least as little as possible on this. I have a good working 4160 holley which i believe is a 650 cfm or was sold to me as so. Would that carb on a cheap aluminum intake work ok on a otherwise stock lg4.. maybe a mild exhaust improvement.. likely only from manifolds back. Could the primarys be leaned way down to improve mileage with the Holley? Thanks
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The holley will work fine. Smaller jets will work to set it up for that engine. Headers are pretty cheap. On my holley i set it up with smaller primary jets and larger secondary jets but both are larger than stock and I see 17-21 mpg with my 350 with a holley 670. The important part is to have it properly adjusted.
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What size main jets would be good to start with? Thanks for the quick reply
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i would start with 72's and go from there
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I am running 68 primarys and 74 on the secondaries on my 350 w/vortech heads and dyno tuned. With these jets it is making 393 hp. With that in mind I would start in the low 60's. My theory with running the larger secondaries is to give it all the fuel it wants when I want to go but save a little when I take it easy. I believe mine were originially 65's out of the box on a 670sa. BTW; check KMJ performance for a cheap intake if you don't already have one.