weird noise

ok so today i took the duster out. got some gas. went to grab a burger. when i got to in n out, it made a strange noise when i turned it off. sort of like the starter was trying to engage and smacking the teeth on the torque converter. after i got my food, i went to start her up and it took 3 tries to get her to start. as soon as i got home it did a different weird noise kinda the pistons were scraping/grinding it sounded horrible. i did notice a little bit of white smoke coming from the exhaust manifolds so im thinking either my head or exhaust gasket is blown.
only thing i did was change the oil and swap out the accel super stock coil for an msd blaster 2.
any clues?