Hello everyone. Was wondering if you could give me some jet/rod combos that would work good with my setup. 455 9:1 compression, 284-88h, stock heads for now, edelbrock performer, TH400 w/2400 stall, 1 7/8 headers, 2 1/2 exhaust, Olds 12 bolt w/3.08 (Want to switch to 10 bolt 3.42), 28 inch tires. Elevation is 5400 ft. Currently primary side is 75 jets 51k rods. Have not measured either air bleeds yet. Secondary rod is a DB. Was thinking of using the first recipe in Cliff Ruggles book. My carb is a 76' 800cfm with APT.
No expert on altitude set ups, but I think you'd need something closer to a 45 rod - better still call Cliff for a tapered rod, and adjust the depth with the APT. He's give you better advice on whether you need to mess with air or idle bleeds for your cam set up...
Completely impossible to make primary jet and rod recommendations without knowing the carburetor number, or even better what are the size of the main airbleeds? For 5000' elevation about one number jet size reduction from a sea-level tune. Having APT makes part throttle A/F tuning much easier. K primary rods are a poor choice for this, as they only taper .005" on the upper section....Cliff
Ok finally got some parts in and measured my air bleeds. The carb number is 17056240. The air bleed in the air horn is .048 and the main casting air bleed is .043. I now have jets in the range of 70 to 78 that I bought. Also have four sets of metering rods. They are .044, .048, 50M, .052. Any help with where to start would be appreciated.
My 17056240 came stock with 75 jets and .045 rods - start as close as you can to that. I don't recall seeing any alternative high altitude settings or part numbers in any Buick shop manuals..... Best bet, get a set of tapered rods from Cliff and dial them in with the APT. Leave the bleeds alone for the time being, and work on the secondary path - notch the air valves for POE transition, open up the wells, tube and POE restrictions to Cliff #1 specs. Also make sure the air valves are opening to a full 85 degrees, or 1.13 inches as measured from the leading edge of the valve to the rear of the bore..... I like a K hanger and CK rods for a starting point....experiment from there.....if you start to open up bleeds, be conservative Just my 2 cents - this combo pulled easy 14.2's on my Stage 1 all day long with the timing all screwed up.. On a sorted motor should support low 13's or better without a problem.
I run a 76, jet with the 52 rod. I go with the biggest jet and thickest needle. No need to use so much fuel when cruising.
WAY too much jet for that carb number and what you are doing. Those units have smaller MAB's, and at or over 5000' are going to need smaller jets. No mention of which metering rods you have obtained for 44, 48 and the 52's? M series metering rods are incorrect for that carb number. Not sure where you obtained the jets? Just be aware that there are 4 different types of jets being sold for Q-jet carburetors, and 3 types are incorrect and will not work right in that carburetor.......Cliff
