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Oddfire · 01-01-2019, 07:30 AM

Quadrajets only came in 3 sizes: 750, 800, & 840. 750s were used exclusively on all Chevrolets. 800s were used on later model Buick Olds Pontiac & Cadillacs. The 840s were a special Hi-Perf breed used only on Pontiac SD 455s for 1 year...1970. The 750s were also put into service on some 6 cyl applications made possible by using smaller Idle tubes & idle down channel & restricting the opening of the secondary airflaps. The 0509 carb you have listed originally came on a 70 truck with a 396 w/ manual trans & destined for Cali. Didn't mean to write a book or cause any problems in this thread but I've been using these carbs for years & thought it necessary to provide this information.

01-01-2019, 07:30 AM	#6
Oddfire Registered User Join Date: Jan 2013 Location: Front Royal, Va Posts: 689	Re: 1970 Quadrajet 7040509 600cfm Quadrajets only came in 3 sizes: 750, 800, & 840. 750s were used exclusively on all Chevrolets. 800s were used on later model Buick Olds Pontiac & Cadillacs. The 840s were a special Hi-Perf breed used only on Pontiac SD 455s for 1 year...1970. The 750s were also put into service on some 6 cyl applications made possible by using smaller Idle tubes & idle down channel & restricting the opening of the secondary airflaps. The 0509 carb you have listed originally came on a 70 truck with a 396 w/ manual trans & destined for Cali. Didn't mean to write a book or cause any problems in this thread but I've been using these carbs for years & thought it necessary to provide this information.