motogotro

I have a 77 L48 car with factory air but the a/c compressor and all brackets are missing. I've done some research and there seems to be some confusion about exactly when they switched from the A6 to the R4 compressor. Some places think it was mid year 76 and some think it was mid year 77. I'm trying to figure out which compressor my car should have so I can try to locate a set of brackets for it. Does anyone have a definitive answer on when the switch was made? If it was mid year 77, is there some way to tell for sure which compressor a car came with? I'm in Texas so I can't be without a/c!

derekderek

Go with the later compressor. Get the brackets for that one. The block heads intake they bolt to is unchanged. The later the better they work. Aftermarket modern is better yet as far as cold air in yer face is concerned... But only vettes used the short water pump. So all those Caprice and C10 compressors with brackets won't do the trick.

jb78L-82

The Sanden aftermarket compressor is better than either the A6 or R4. The later R4's are really not very good at cooling like an A6 and are not very durable..Personally, I think that they are junk.

The R4's came out since they were much lighter and smaller than the A6 but they are NOT equivalent for cooling power and durability. The R4 on my 78 C3 was dead at 25,000 miles back in 1983. I had 2 A6 compressors on other cars that were still working at 170,000 miles and 120,00 miles, respectively.............and cooled like the Arctic air with R12 freon which my 78 C3 R4 never did....

Easy Mike

The change to the R4 compressor was during the 76 model year run. Your 77 would have had the R4. The 77 AIM shows the AC installation and the brackets and hardware you will need for mounting the compressor.