According to the 1975 Buick parts book, models 43327,37,69 are listed as Skylark with an L6. Models 44437,67,39,69 are listed as Skylark Custom with a 350-2. GS's are listed as 43437,67 with 350 or 455. What I am suspecting here is that these are BASE engines and do not take into account for OPTIONAL engines. Not all V8 Skylarks were Customs and I am sure there were some 4bbl ones at that. What you likely have is a Skylark (not Custom) that has the optional 350 V8. The basic Vin would indicate an L6 and not take into account the option. This is a good reason for adding the engine code to the Vin in 1972. Mark
