I remember working on these at the Buick dealer in 78. It has the fender ports the other GM's didnt have. The 403 Olds was the engine to have in the full size Buick.
The 403 was the engine to have in anything. They were much like the 340. They only came one way. Hot. At least for the time. I had a friend when we were in school who had a 79 Trans Am with a 403. That was probably the fastest production I have ever been in. Fastest. Not quickest. We had that car going so fast, the T tops blew out of it. I know we had to be goin more than 140 cause the broken line was solid and that happens right around 140. It was impressive for a stone stock automobile.