There should not be a fuse, able to shut down the engine. If everything shuts down, then the main circuit is being interrupted, and it should not be fused; but F-linked. The Fusible link makes it possible to have short-term power overloads, yet not cause an F-link meltdown, or a blown fuse.
Of course it could just be a sloppy connection at the back of the ammeter or the ignition switch. Or the bulkhead connector. Or the ballast resistor, or a faulty coil, or a bad splice, or a loose connection at the starter relay. or a bad engine ground. 'Cuz that is the main-circuit.
But really you never said WHAT fuse it is blowing.....................
Is it the one that powers up the EFI?, or
is it the one that powers up the MSD?, or
Is it the one that powers up the fuel pump?,or
is it the entire main circuit?
Do you have one fuse doing all those jobs? and are they all powered through the ignition switch?
But the thing that confuses me is that you say you reached home on a running engine, shut it off, and then it will not restart,because of "a" blown fuse . Does that mean it will not crank? Or it cranks but will not start.
If it cranks but will not start, then it seems to me you will have to figure out which circuit is overloading the fuse;either the pump, the EFI, or the MSD, or quite possibly something else.Since we have no clue how you wired it, we really have no clue where to start the diagnoses.
But Ima gonna guess that the fuse cannot handle everything that is used during the starting procedure; such as the above three plus perhaps the brakelite circuit if you are standing on it, plus the starter relay, etc
or relayed with separate switches
