1. Gear ratio is on the trunk sticker for your car. TRhere is a code,and it can be deciphered by a Chevy dealer or by looking in the service manual.
2. Track. The 94 Caprice has a wider rear track than the earlier cars. However, the 9C1 axle retained the narrower track. Use of the narrower axle will change the look of the car, probably for the worse.
3. Brakes. If your 94 has the 7 5/8 axle, which is probably does, the brakes from the 9C1 axle will not fit. If the 94 does have the larger 8 1/2 axle, then the larger brakes from the 9C1 will bolt onto the axle you have in the car.