83 ramcharger need help trouble shooting

[74duster]

I Just got an 83 ramcharger for free from a friend who moved out of state and the battery blew up on his brother when he was driving it. I replaced the alternator and voltage regulator and it turns over the starter is drawing over 300 amps and its only supposed to draw about 120 amps. The ECU blew a hole in the back and I couldn't see it until I took it off. could that of been caused by the battery blowing up or was it because the starter is drawing too many amps. I didn't here a pop or a weird noise when it was turning over. Any help would be appreciated. Is there any thing elts that I should check that may have been damaged when the battery blew up.

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