Additional searches and I think my question is answered. My dealer invoice does indeed list the WS6 package for $151. This matches info below. If anyone has anything else to add, please do!
Originally Posted by John Witzke
68ragtop,
"The WS6 Trans Ams Special Performance Package did include the W72 engine at the very beginning og the 1978 model year. I have confirmed as early as Oct 1977 you could order a W72 Trans Am minus the WS6 package even though a memo from Pontiac dated Feb 22 1978 explains the seperation of the two packages.
In Feb 1978 dealers could no longer order the W72 engine with automatic transmission as stock (dealer inventory) orders. The deadline for customer orders was March 20 1978. The latest build date I have recorded for a W72 automatic car is first week May 1978 which would be in line with the cut off date.
Production of the Y88 Trans Ams began Jan 1978.
I believe you are refering to the window sticker or invoice when you mention the pricing. The build sheet just list options, etc with no pricing. A W72 Y82, Y84 or Y88 car produced with WS6 would be $151.00. Some window stickers or invoices may list the options separate, W72 $75.00 and WS6 $76.00. Or they may just say WS6 Trans Am Special Performance Package $151.00. I have a 1978 W72 Y82 invoice showing a ship date of 2/10/78 (1/23/78 build date) with only the $151.00 WS6 option listed. In comparison I have a build sheet for a base 1978 W72 Trans Am with WS6, build date 2/10/78 and the window sticker only list the WS6 option $324.00.
A non W72 special edition car with WS6 would be $76.00.
1978 W72 cars were produced at both Norwood OH and Van Nuys CA assembly plants.
Hope this helps.
John Witzke
POCI Tech Advisor
1977-79 W72 Performance Package
www.78ta.com/w72.htm"