NEWOLDSMAN

can anyone tell me are the a/c compressors different from sm block to big block. And how about the mounting brackets. Does any aftermarket company sell the mounting bracket?

joe_padavano

During the years that the BBO and SBO were both in production (1965-1976), all accessory brackets were dual-compatible. Since the only external difference between the BBO and SBO is the deck height, the brackets were designed to either bolt only to the head or block (thus eliminating the deck height as a variable) or had two sets of bolt holes to account for the deck height difference. In those years, the only A/C compressor used was the massive A6 compressor.

Starting in the late 1970s and through the end of 307 production in 1990, Olds used the smaller R4 compressor. The brackets for this compressor only fit the small block (since they span from the head to the block), but simple welded on tabs will extend the bracket to fit the BBO. Many have done this when swapping a 455 into a G-body.

Aftermarket support of brackets is limited due to limited popularity of these motors. The few that are available are pricey.

Olds64

I've thought about using 307 brackets to mount an R4 compressor onto my BBO. The orifice tube AC system used in the Oldsmobiles in the 80s and 90s is a simple systems that easily converts to R-134a. Plus, the compressor doesn't weight 80lbs.