hello all - just started to have a random problem with starter motor and battery issues. mk IV with blueprint 427 finished this past may and everything going very well until last week have about 1400 miles so far suddenly won't crank over battery showing approx 13.5 volts then starter motor won't engage flywheel and just spins even with ignition off have to use battery cut off to stop starter motor now if battery cut off switch is "on" the battery cables get very hot real quick i have checked engine block ground to chassis battery ground to chassis and fuse block ground to chassis all are tight and seem ok any thought ideas truly appreciated

thank you
dave s