When the emissions BS hit, the big 3 did the same thing to the smallest small blocks. They reduced intake lift about 0.050". I had a 1982 Blazer 305 4 barrel with the 700R4 overdrive. On level highway it would cycle between D and OD. Poor vaccum, power and fuel economy. When the General came out with the hi output 305 for the Camaro, they used a 350 cam. Valves were bigger and combustion chamber a bit smaller. That lead me to check the TRW cam catalogue. The lowest Chev cam was the 305. There was another cam and then the 350, another cam and a "RV" cam. I bought the RV cam and installed with new lifters. Driveability was greatly improved as well as mileage.