Newbie with Decoding question

[tall455]

 Greetings to the forum! I've arrived here by looking for a good Qjet for my 1971 Buick GS. I bought and read Cliff's Qjet book and decided a good base carb to start with would be a 1976 Qjet. I found a nice buy on a rebuilt carb on ebay. The carb number is 17056564 2722. If I am decoding it correctly, it is a 1976 Pontiac auto transmission carb with California emissions. If I am decoding the date code correctly, it was built on the 272 nd day of a year ending in 2 - like 1982. That doesn't make sense to me. I also do not know what is the difference in a "California emissions" Qjet and a "49 state" Qjet. I equate emissions controls with poorer performance. Is there something about this carb that hurts performance that could be modified to make it perform like a "49 state" Qjet? Thanks for any replies.

[omaha]

    It seems what you might have is a "service replacement carburetor".  These were made after the original carbs were made and used in dealerships for service replacements. Sometimes theu were made years after the original application carburetor. The ID number of the carb was not changed but the date code stamp changed and indicated the actual build date.  I am not sure of this 100% but  I think some of them were stocked on the shelves at some dealerships to sell over the counter.
     As far as the california carb emmision is concerned, it really does not amount to much. Maybe slightly larger air bleeds and slower opening secondaries. Maybe slightly leaner jets sometimes. BUT, remember, this is 1976 were talking about here. ALL carbs were set up just about as lean as they could run them. There wasnt much difference from the cali carb to the 49 state version. Rochestor was at the top of the heap as far as emission regulations  goes.  I guess they did a few things to make the tree-huggers happy down there in LA-LA LAND and I dont think it really took to much to do it.  The tree huggers were happy with their now slower vehicles and gee, when they went up in the mountains, they were set just about right. (less air = richer mixture) .  anyway, FWIW, dont worry bout the CALI CARB number. All shortcomings can be absolved quite easily.......ENJOY!!

[tall455]

 Thanks for the informative reply! My plan is to now disassemble the carb and determine just what jets, rods, etc.. it has. Then I'll post back for suggestions to calibrate for my application. I have a heavy (4000 pounds) 1971 Buick GS convertible with a 455 engine, TH400 automatic transmission, and 2.93 posi rear end. Attached are photos of the carb I.D. # and overall view. I think I have a great starting point to improve upon.

[Cliff Ruggles]

EXCELLENT carb, identical to the one I use on my own engine.

Setting it up is easy.  When you are ready, call the shop, provide the carb number, and all the engine/drivetrain/vehicle specs, we will send the correct components so it's basically just "plug and play"!.....Cliff

[tall455]

Thanks for the encouragement! Where I have gotten bogged down is in how to get the hole sizes correct for the air bleeds, idle down channel, accelerator pump discharge holes, ect.... I bought a "mini" drill bit set, but it turned out they were too small - just .011 inch to .031 inch. Then I looked at buying a pin gauge set in order to determine individual number drill bit sizes needed, but in order to cover the range of diameter sizes needed, I would need to buy two pin gauge sets: one from .002 to .060, the other from .061 to .250. Together they would cost about $100.00. I need to put that money toward the rebuild kit, not gauges that I would only use once. If I contact your shop with my carb number and information about my car and engine, could they recommend what number drill sizes I should buy in order to get the hole sizes correct for my application? Thanks again! - Robert

[Cliff Ruggles]

You are lucky in one respect, that carb does not need any modifications to the idle or main airbleeds.  It may need idle tubes enlarged, idle down channel restrictions, and idle bypass air, but no other mod's are needed to the main components when setting it up.

Most likely jets and metering rods will need upgraded as well.  Not sure exactly what recomendations to make without knowing the specifics about the application?.....Cliff

[tall455]

Thanks Cliff - thats good news. My car is a 1971 Buick GS convertible. It is heavy - with me in it and 1/2 tank of gas we weigh 4100 pounds. It has a 2.93 posi rear end and TH400 automatic transmission. The torque converter stalls at about 2200 RPM. The engine is a 1973 455, bored .030 over with 8.5 to 1 forged pistons. The intake manifold is stock cast iron. The heads are moderately ported stock heads, stock valves with a 3 angle valve job and "Stage 1 spec" valve springs. The specs on the cam are 230/242 degrees duration, .490/.488 lift, 114 degrees lobe separation. The rocker ratio is stock 1.55 The exhaust system is headers with 2 1/2" dual exhaust and dynomax mufflers. At a track 1000 feet above sea level, I ran a best of 14.1 seconds at 99.5 mph in the quarter mile, shifting at 5400 RPM, but only turning about 3800 RPM through the traps because I do not get to third gear until a few hundred feet from the finish line. Best regards - Robert

[Cliff Ruggles]

For the 455 with 8.5 to 1 compression and that much camshaft, it's going to need some idle and off idle fuel, and re-jetted as well.  I'd use the upper end of the 3rd "recipe" in our book. 

I have the correct jets and custom metering rods in stock, and the correct power piston spring as well.

Not much else will be required, aside from a high flow Viton needle/seat assembly, and good accl pump to hold up in ethanol.......Cliff

[tall455]

Thanks for the recommendations! I forgot to mention that I am using Crane "High Intensity" fast bleed down lifters. They work similar to Rhoades lifters except they do not bleed down so fast that the lifters "click". They do work well in "taming" the idle.  Have a good 4th of July weekend - I'll call your shop Tuesday and get the proper parts on order. Best regards - Robert