I hope you are putting the listed parts in the motor:
Melling High Volume Oil Pump
Oil Pump - High Volume M95HV
Oil Pump Screen 95S3
You will be able to reuse the oil mounting bolt. When you re-intall the oil pan, get some modeling clay and press it against the pickup screen and the bottom of the oil pan, that way you know how much to adjust the pickup screen to the bottom of the oil pan. Clearance here is very important.