NHRA's ruling on "Single Booster" Quadrajets

Danny Ashley · 09-01-2007, 11:12 PM

I was informed Friday at Indy by Travis Miller that the 1971 Pontiac quadrajet we in the business refer to as the "Single Booster" will only be permitted on the engines that were originally equipped with them. For those of you who have never heard of them , here's the story. All Q-Jets ,except these, have a main and two booster venturis. In 1971 only, Pontiac had Rochester build a Quadrajet without the larger of the two
booster "rings". # 7041263 was put on the 400 & 455 "standard" engines. #'s 7041267 & 7041268 on the 455 H.O.'s and #'s 7041270 & 7041273 on the 455 Ram Air's. The kicker is that not all 1971 Pontiac Q-Jets are single boosters. # 7041262 was put on the "standard" 455 while # 7041264 on the "standard" 400. The story goes that some customers complained of a low speed lag with the single boosters and the dealerships would replace them with # 7041262 or 7041264. NHRA believes that the single boosters flow more air-fuel mixture and would be an "unfair-advantage" when used on another engine. Racers have been using them for years because the main venturi does measure 1.093 which is the correct measurement for all makes of engines that require this specification for the smaller of the two sizes Rochester made. The other is 1.218" for the 800 CFM. So if you know of any racer that is running a single booster, please tell them the ruling because I doubt that we'll read about it in National Dragster. I don't wan't anyone to be surprised in the barn. I had one of these to do for a Pontiac Stocker racer ( 1972 455 ) when I returned from Indy so I called and and gave him the bad news. What a shame because they are rare and expensive. I'd like to clear up a mis-conception about what Q-jets racers can use. While at Indy, some people told me that if you run a Chevy that calls for the 1.093 ( 750) carb., you can only use a 7029207 or an Edelbrock 1901. First, NHRA doesn't care about what numbers are stamped on your Q-Jet. Second, they don't care if it's a front or side fuel inlet. And third, it doesn't matter to them if it's a smog style( 1975 and later ) or the non-smog type ( 1974 and earlier). So what does all this mean? It means that if you run a Chevy, you can run ANY Chevy, Buick, Olds, Pontiac, or Cadillac from any year as long as it has the correct size venturi excluding the single booster of course. Or you Olds guys can run a Chevy, Pontiac, Buick, or Caddy.Or you Pontiac racers can run.... well you get the picture. I haven't forgotten you 800 CFM guys. The same rules apply to you. Can't find a nice core for that 70's B-O-P-C? Look no further than an Edelbrock # 1903 or 1904 which is a late smog style Chevy. When I had my Pontiac stocker I went through the barn using a Chevy carb. and it's current owner has also paid a visit to NHRA's "Party" without any problems. Hope this helps. Danny @ Q-jet Performance.

09-01-2007, 11:12 PM	#1
Danny Ashley Member Join Date: Nov 2001 Location: Marion,In. Posts: 267 Likes: 60 Liked 110 Times in 29 Posts	NHRA's ruling on "Single Booster" Quadrajets I was informed Friday at Indy by Travis Miller that the 1971 Pontiac quadrajet we in the business refer to as the "Single Booster" will only be permitted on the engines that were originally equipped with them. For those of you who have never heard of them , here's the story. All Q-Jets ,except these, have a main and two booster venturis. In 1971 only, Pontiac had Rochester build a Quadrajet without the larger of the two booster "rings". # 7041263 was put on the 400 & 455 "standard" engines. #'s 7041267 & 7041268 on the 455 H.O.'s and #'s 7041270 & 7041273 on the 455 Ram Air's. The kicker is that not all 1971 Pontiac Q-Jets are single boosters. # 7041262 was put on the "standard" 455 while # 7041264 on the "standard" 400. The story goes that some customers complained of a low speed lag with the single boosters and the dealerships would replace them with # 7041262 or 7041264. NHRA believes that the single boosters flow more air-fuel mixture and would be an "unfair-advantage" when used on another engine. Racers have been using them for years because the main venturi does measure 1.093 which is the correct measurement for all makes of engines that require this specification for the smaller of the two sizes Rochester made. The other is 1.218" for the 800 CFM. So if you know of any racer that is running a single booster, please tell them the ruling because I doubt that we'll read about it in National Dragster. I don't wan't anyone to be surprised in the barn. I had one of these to do for a Pontiac Stocker racer ( 1972 455 ) when I returned from Indy so I called and and gave him the bad news. What a shame because they are rare and expensive. I'd like to clear up a mis-conception about what Q-jets racers can use. While at Indy, some people told me that if you run a Chevy that calls for the 1.093 ( 750) carb., you can only use a 7029207 or an Edelbrock 1901. First, NHRA doesn't care about what numbers are stamped on your Q-Jet. Second, they don't care if it's a front or side fuel inlet. And third, it doesn't matter to them if it's a smog style( 1975 and later ) or the non-smog type ( 1974 and earlier). So what does all this mean? It means that if you run a Chevy, you can run ANY Chevy, Buick, Olds, Pontiac, or Cadillac from any year as long as it has the correct size venturi excluding the single booster of course. Or you Olds guys can run a Chevy, Pontiac, Buick, or Caddy.Or you Pontiac racers can run.... well you get the picture. I haven't forgotten you 800 CFM guys. The same rules apply to you. Can't find a nice core for that 70's B-O-P-C? Look no further than an Edelbrock # 1903 or 1904 which is a late smog style Chevy. When I had my Pontiac stocker I went through the barn using a Chevy carb. and it's current owner has also paid a visit to NHRA's "Party" without any problems. Hope this helps. Danny @ Q-jet Performance.