[combinefixer]

Originally Posted by William

The first two ZL-1 Camaros were rushed into production and delivered to Fred Gibb Chevrolet December 31, 1968. The #1 car was prepared for drag racing and failed tech inspection at its first event in AZ. It had been built with the production L-72/L-78 #3959164 #4346 780 CFM vacuum-secondary carb. At that time, it was thought to be a supply problem. However, the 850DP carb had been in production by that time; 1968 dated carbs are known.

A likely reason for the substitution was the production ducted hood air cleaner was not designed for use with a double-pumper carb. The air cleaner had a 90° vent tube on the rh side that interfered with the secondary accelerator pump. It appears likely that Chevrolet Engineering knew this; box #176 on the Chassis Broadcast Copy for #1 & #2 shows carburetor code ‘GE’, the production code for the 780. [Carbs were installed at the Norwood assembly plant].

In interviews with Fred Gibb, he stated the 50 cars he received were built with the 780. In magazine drag tests [Super Stock May ’69; PHR July ’69] of the #1 & #2 ZL-1 Camaros, the ‘street’ ZL-1 was tested with both carbs. Gibb stated Chevrolet retrofitted the remaining cars in stock at the dealership early in 1969. It is not known what modifications were made to accommodate the 850DP.

As for the other 19 ZL-1 Camaros, #3 and #51 were built during the same time span as the Gibb cars. #3 was photographed for a road test feature in the August 1969 Hi-Performance Cars magazine. The engine photo shows a 780 carb, choke plate intact. One of the last ZL-1s [built May ‘69] was raced for many years, sold to its second owner in the late ‘80s. The original owner stated at the time that he swapped the 780 for an 850DP purchased at a speed shop, had the receipt to verify.

37 of the 50 Gibb ZL-1 Camaros were returned to Chevrolet and re-invoiced to other dealerships. By that time, they had been retrofitted so it is likely their original owners assumed the carb was original.

Considering what is known, there is little reason to believe any ZL-1 Camaro was built with the 850DP.

The vintage story/photographs seen here were the work of Ro McGonegal, free-lance auto journalist in the '60s. While it is widely believed the 'street' ZL-1 in the feature was the #5 car, Ro recalled the testing took place on an unusually warm day in January, 1969 at KCIR near Harrell's shop. The only two ZL-1s in existence at that time were #1 & #2.

Incredible history lesson! Great thread.

Wonder why GM didn’t spec the Holley “3418” 850 cfm vac sec carb that the L88’s had been using vs the L78/L72 4346 carb?