Short problem small block
Happy you found 'er. LOTS of us have made that mistake in times past.
One time I had a bad battery, bought a new one.
CLEANED the battery cables, but NOT the new battery posts. They "looked" fine
Put the new battery in and it acted JUST LIKE the old one. I just could not believe it.
Finally started to think, got out the test lamp, and there we were.
I was about 17-18 when I pulled that stunt.