Intro and question

I'm just what you guys need, another member with WAY more questions than answers............
I currently have a 428 in my 76 f-250 4X4. The 428 was in a 62 F-100 4X4 I purchased in 1978. I ran the part numbers and it seems to have all the right parts to be a CJ or possibly a SCJ due to the fact it had a lug on the dampener spacer that somehow got lost while it was stored. The numbers on the rods don't match either the CJ or SCJ tho.. I got the 428 out of storage a few years back rebuilt it and installed in the 76.

The machine shop balanaced it by removing meat from the flywheel and the motor is very smooth has about 40K miles on it with no vibration issues.

I also have a 58 Fairlane 500 2 dr. hardtop with a 300 horse 352 and cast iron Cruise O Matic.

I want to plant the 428 in the Fairlane and back it up with a C-6.

Do I NEED the Crank Lug?

Can I buy a flexplate that will work?

What harmonic balancer should I use?

Thanks, and sorry for the long first post...