It would help a bunch if you posted what the original engine and brackets were from as well as what the new engine is from (year, size, etc). Also, does the car have power steering, air conditioning, smog pump, etc???? Such can vary within the same year/car/engine family. Post info about which accessory was on each side of the engine....alternator was on xx side, power steering pump was on drivers side, etc. Was the original engine a V belt engine or a serpentine engine? If V belts, how many belts?

The bolt patterns on Chevy small block heads may look the same (three bolt holes tapped) but there are two different patterns. Also, some intake manifolds have an alternator bracket attachment while others use a stud on the water outlet. Some intakes have vertical mount holes for an A/c compressor while others dont, etc.