Good info, should get you there.
I would use a GM HEI rather than aftermarket, just my opinion. Many have aftermarket and really like them. If you do go aftermarket try to avoid the MSD "ready to run" distributor. I had so much trouble with one I sent it back and got a used GM.
"ready to NOT run"

I use a relay to power the HEI, it can get you more voltage at the distributor, and you don't have to remove the original resistor wire, 9 volts will switch the relay. If you ever want to go back to pure stock the wire is still there. After installing a 140 amp SI alternator, my dash volt gauge still showed only 12 volts. I checked the voltage from the alternator through the firewall junction box, to the ignition switch and from there to all the components and lights. Voltage drop was amazing. I had 14 volts at the alternator, 13 volts at the junction block, 12 volts at the ignition switch, 11 volts at the light switch and only 10.5 volts at the headlights. there was a bit of a voltage drop at every junction. 46 years of age, dirt and corrosion. I've since cleaned things up and replaced a few things for better circuits. I did run the power wire for the ignition relay from the main power source off the alternator and get 14,8 volts at the distributor. One case where more really is better.