Hi guys I have an 86 iroc z that originally had a 305 in it but I engine swapped it for a 350, so my question is should I change the computer for a 350 ECM or will the car run fine with a 305 ECM ? And if I need the 350 ECM what year doesn't have the VATS programmed into it or do I just need to wire in resistors? to make the VATS not work essentially

Also I want to know if anyone has an ECM for sale for either with the PROM if possible