"T/A 6.6" or "6.6 Litre"
Here is another one of those long debates that people get into over the engine designations. They always argue which is right for their car.. is it the "6.6 Liter" or "T/A 6.6"? Well here is the simple answer. If your car has the W72 Pontiac 400 engine, then your engine designations listed on your shaker scoop should be the "T/A 6.6". If you have the L78 Pontiac 400, or the Oldsmobile 403 engine, then your shaker scoop engine designations should be the "6.6 Liter". Now you can prove to your friends and end that argument once and for all with this page. I have included a copy of the Original Dealers Manuals from 1977 which states these engine sizes and designations. Need more proof?
As you can see from this Listing, it clearly states that the L78 and L80 engines were labeled as "6.6 Liter" and the W72 engine was labeled as the "T/A 6.6"
1977 vs. 1978 vs. 1979
Now, this is the listing and how it was for 1977 when the W72 engine first came out. So, in 1977, if you had the L78 Pontiac 400 or the L80 Olds 403, then you got the "6.6 Liter" shaker decals and if you had the W72 Pontiac 400, then you got the "T/A 6.6" shaker decals. In 1978, if you had the W72 Pontiac 400, then you still got the "T/A 6.6" shaker decals. BUT, if you had the L78 Pontiac 400 or the L80 Olds 403, then you got NO shaker decals. For some reason they left them off of there in 1978 (except for Special Edition Cars, they always recieved shaker decals and followed these same rules). For some reason in 1978, they also left the front nose bumper name decal off. Now, in 1979, there was no L78 Pontiac 400, only the L80 Olds 403, or the W72 Pontiac 400 with a manual transmission only. So again, the W72 4-Speed had the "T/A 6.6" and the L80 Automatic had the "6.6 Liter".