73 340 questions ....any help appreciated

1. buy a good drill bit and DIY.
2. Do not overcam with a 3.23 gear. Follow the guidelines of the cam manufacturer for gear, converter, compression ratio. A 268 or 272 duration, 2500 stall will haul the mail for a street car with 3.23 gear. You also mentioned you have double springs, run the springs required by the cam manufacturer.