Ayuh,... Is this a reman motor, rebuilt motor, or new from Chevy motor,..??
The cam in it will run just fine in a boat,.....
Don't reuse the old cam,....
If you want a new cam, find a idle to 5000 rpm, RV cam for it,....
Ayuh,..... Welcome Aboard,..... Pullin' the motor would be the easiest route,.....
Otherwise, Pull the drive, then lift that side of the motor, pull the motor mount, then drive in a new core plug,....
Ayuh,..... When cranking on the starter, the ignition is powered by the outer tiny terminal on the starter's solenoid,....
When the key is released to run, the ignition is powered by the purple wire ignition circuit,....
Ayuh,..... Agreed,..... It's a long ways from the battery, up to the key switch, 'n back to the solenoid, on tiny wires,....
Usin' a slave solenoid gives ya good voltage, where, 'n when ya want it,....
Ayuh,.... Welcome Aboard,..... I think that would be a very wise decision,....
Zero parts for those drivelines,....
Yer parts might be valuable to someone doin' a "Historical" restoration,....