Fusible link or not?

Not usually. A fair amount of power needs to go through the relay to the starter when starting.
Where is the alternator output connected?
Presently I am running the 60 amp denso alternator through the normal route through the amp gauge. After I get it running, (a couple weeks), I will bypass the Amp gauge as MAD Electrical explains. I just made enough changes to confuse mere mortals. If we are still quarantined and I cannot go to the track, I may do it earlier. This motor was broken in on a run stand with a carb and regular fuel pump. Many new puzzle pieces.

The 30 amp is just for the distribution block from the starter relay. Not from the battery to the starter relay. Do I need a fuse between the battery and the starter relay. I have never seen that.