OLDsBARRY

From what im picking up factory speced carburetors for '71 442 (includ w30) were:
7041253 1971 4 455 Man
7041257 1971 4 455 Auto
Anyone seen what they think is factory original Carbs to the car but not these numbers?

For a number of years i was in the manufacturing end of a Tractor Company. #1 rule was
DO NOT STOP THE ASSY LINE
Substitutes had to be made. Hard for me to believe it didnt happen at Olds.

http://www.teufert.net/carbs/olds.htm
7040253 1970 4 455 M OLDSMOBILE CUTLASS/442
7040255 1970 4 350 ALL OLDSMOBILE CUTLASS/442 W31
7040256 1970 4 455 M OLDSMOBILE W30
7040257 1970 4 455 A OLDSMOBILE CUTLASS/442

joe_padavano

Olds had to warranty every car they made, issue repair information to the dealerships, and provide appropriate spare parts in the parts network. In addition, the 1971 model year cars were emissions controlled and had specific parts as a result. They did not randomly grab whatever was lying around the factory floor and bolt it on contrary to every story you hear from someone trying to get stupid money for a one-of-none car. Any time an assembly line substitution was make, it was fully documented with engineering documents, manufacturing instructions, and dealer service bulletins. There are examples of this, such as the 750 or so late 1967 production 330 motors built using 1968 350 block and head castings. There is both a technical service bulletin and notations in the parts book that document this change. Same thing goes for the changeover from the rubber "j-tube" on the t-stat housing to the metal one, or the change from the '251 to the '254 Qjet on the 1968 W30 motors.

To answer your question, yes for the 1971 model year, all 442s (including W30s) with MT got the '253 carb and all with AT got the '257. This is documented in the Chassis Service Manual, the Rochester Carb Data Book, and the 1971 Engine Assembly Manual. Specifically, the '253 carb was used on engines TA, TN, and TU, and the '257 was used on engines TL,TT, TV, and TW.

Andy

BAM, THE word-is spoken.. awesome answer