+2 One excellent example is the carburetors they used. Each carburetor was calibrated exactly for the application, and they did a very good job of it. That fact is also a problem at the same time because each Quadrajet, for example was dialed in to provide the engine with the fuel in needed at every level, but had to meet emission standards in place as well. That is the biggest reason many fall short because from the day I got into this hobby until now EVERYONE changes many items when they rebuild these engines taking them often pretty far from the original parameters. So the carb, and often the distributor as well fall short in adding enough timing/fuel to keep things happy. Even worse lack of knowledge on the part of the folks involved with these engine projects lack the skill sets to get the factory parts up to par, so off they come and into the Summit catalog the owner/engine builder goes to replace them with "high performance" aftermarket parts. Sadly, in most cases if the knowledge were present to "tweak" the factory parts for the engine changes a lot of money could have been saved and the engine would have made just as much power as well. I'd also add here that factory parts, as much as many folks hate them are a LOT better choices in long term service. Case in point. I use a plain old 1977 Pontiac Q-jet on my 455. It has been in service now on 5 different engines since 1985 ranging from apprx 350hp to just shy of 600hp. I've had my engines on the dyno, and loaned out my carb scores of times for dyno and track testing, plus I've tested it many times myself at private track rentals carry as many as 8 different carburetors to run against it. This has included Demon 850's, Holley HP950's, Holley 4781-2 850's, Edelbrock Performer/Thunder Series carbs, factory "high performance" Thermoquads, and even custom build Holley style carbs built by "experts" in that field. As much as my dyno shop hates the ugly Q-jet NOTHING they have pulled out or we've carried along with us and back to back tested against it will outrun it anyplace. Even better the Q-jet is NOT a highly "modified" part, as a grinder or sanding roll has never touched it. It has minor venting mods to keep all the fuel in it on hard runs and recalibrated and tested over many years on the dyno and at the track to be dead nuts on the money in all areas. Matter of fact the dyno shop I use has told me on more than one occasion to "never touch it". I'll also add this. I've been part of quite a few magazine articles, including the Popular Hot Rodding Engine Masters edition. I've been asked more than once to install a "high performance" aftermarket carb, and intakes a few times, and a couple times MSD billet distributors with 6AL boxes, to "see how much power this engine will really make?". Every single time we LOST power going to something else. Even when we carried the same parts to the track as part of the testing the ugly Q-jet and stock intake has ran quicker in ET than anything else back to back tested against it. The only problem with that sort of testing is than in this industry you are allowed to test aftermarket parts against stock ones, but IF your stock parts make more power or run quicker at the track don't expect to see much of or any of it in print when the magazine comes out!.........FWIW........Cliff
Ha, Ha, I worked at AC Rochester off Averill St. Flint MI in the early 90's. The Fuel Labs were much smaller but still semi clean rooms and all injectors and pumps were still tested with Stoddard solvent. I saw and heard about these large carb labs with the way over kill clean rooms. There were a couple of Carbs on display but they were all computerized versions.
I have always enjoyed the ‘wow’ factor of a quick, smooth running car that has stock parts like a Qjet. Here’s last year’s BSA field and their qualifying times; all but two are running Qjets (as per the rules). Patrick
Wow I swear I could smell the new car smell while watching this. Actually a heck off alot more involved that I could of imagined in making a car.. On one note I don't how my Fathers new 66 Wildcat passed the water leak test.. It just about leaked from both front and rear windshields from about day one
I bought a few X carbs years from a guy that worked at Rochester. He said they were fully blueprinted and used for testing. Need to dig through my stuff some day. Seem to remember one was for an application that I would not have had need for and I sold it and made some $$$. Sorry it was in the late 80s....
As much as I LOVE to see folks running super-quick with factory carburetors in racing classes one has to understand that the carburetor is a small part of a big plan in that arena. I've done a few SA and Super Stock Q-jets, but a LOT more Pure Stock and FAST carbs. I find it amazing how fast those folks are running considering the vehicles look showroom stock and must use narrow bias ply tires! With many other drag racing classes they are leaving on the floorboard with converters flashing well over 5000rpm's. The carburetor at that point is nothing but a precisely calibrated "toilette" dumping fuel into the incoming air mixture in correct proportions to make the best power over a vary narrow load/speed range. You could literally carve one out of a block of wood and if it was big enough and mixed the fuel well enough with the incoming air the car would be just as quick as with anything else you tried on it.........FWIW.......
I think I read that both the 66 GS Q-jet " the 425 Q-jets also" and the 67 GS400 Q-jet had side inlets for the fuel. I know by experience the 66 did. Was there a reason they changed it later or more for clearance issues?
I don’t recall any “clean rooms” at Rochester Products for carburetors. The flow test area was not a clean room, just climate-controlled. The “clean rooms” were reserved for fuel injection, which was in its infancy when I was there. Cadillac Allante had their own clean room, Saturn demanded (and received) their own clean room (lol) but most of the fuel injection action surrounded TBI and port fuel for Chevrolet. In one of my stints there, I was a production supervisor for the V6 Port Fuel assembly line. As a young kid (early 20’s), I’d hop on the line and help out, as well as move parts into position to get more units build, etc, and boy did I get my first taste of the UAW by stepping on some toes (me being naive). I messed-up the OT list once during Thanksgiving, and somehow one union employee got my home phone and called to let me know about it. They sent us students to Grand Rapids, Michigan to tour the AC/Delco facility there too. I can’t remember if there were one or 2 locations there. They made the fuel injectors and lifters in Grand Rapids. Talk about a complete opposite in manufacturing. Wowser, those lifter pressing/stamping machines were really something. We also got to see the “new” lost foam casting of Saturn blocks and heads. A foundry is not a place for un-hearty people! Back in Rochester, NY, there was a second manufacturing facility under RPD’s umbrella, called “Lee Rd”. It was not too far away from the Lexington Ave plant, where the carburetors and fuel injection were made. Lee Rd. was a much newer facility and they made emissions control devices such as EGR valves, diverter valves, vapor management valves, purge valves and charcoal canisters. They probably made more things too, but I think I’m at the end of my Prevegen today. That place was boring compared to Lexington Ave. To make different models of carburetors and fuel injection under one roof took a lot of people and cool machinery. But when carburetors were phased out, the amount of people and equipment that became unnecessary was significant. Fuel injection was much simpler to build, and parts of the plant were going dark in the late 80’s. Who knows what it’s like in there now, or what exactly they make.
"I think I read that both the 66 GS Q-jet " the 425 Q-jets also" and the 67 GS400 Q-jet had side inlets for the fuel. I know by experience the 66 did. Was there a reason they changed it later or more for clearance issues?" The factory always did things for a reason. Might have been as simple as making the fuel line shorter and easier to install, or added clearance for something on that side of the engine, ease of routing it up thru accessories, brackets, etc. You know that if you save 8" of steel fuel line and multiply it by the total number of cars in a production run it adds up to a LOT of weight and cost savings..........
I have these carbs. 67 and 73. Bought them from a guy that said he worked for Rochester Products. He claimed they came from engineering dept. Who knows....
Cliff, here's a question for you. This is a carb supposedly from a 1966 Skylark GS equipped with the Q-jet engine option. It was a very low production option, 136 cars. This carb is missing the stamped round aluminum ID tag but does have these numbers stamped here. It also has an' 'x' in the casting which you can see above the handwritten pn. Does the 'x' indicate anything special, such it being an engineering unit? Any thoughts on the stamped numbers?
Nothing special about those that I'm aware of. It appears to have the raised area where the tag would have gone but the hand stamping on the rear of the carb indicates someone spent some time with it at some point. Not sure if that's at the factory or somewhere else along the way. You'd think if it was done at the factory they would have stamped it in the same location as the 1968 and later units.......
Thanks Cliff. I was wondering if it was an engineering piece.... especially with the 'X'. It's missing the round ID tag and there are no stake marks to hold it in, if there ever was one there. It's being sold at a premium price. Can't determine if it's a run of the mill production carb ('66 Riv with 425) that had the tag removed and got stamped, or if it's something special.
