Being an 83 model car mate you will find it very hard to find an engineer that would pass it off being that alot of the adr's changed from 78 onwards.You would probly need to have a full emission's test done and it would need to comply with the adr's set for your car not easy with a draw through turbo setup and the test's can cost up to $5000
.Easiest way to get it rego'd would be put it back to stock or if you want to keep it turbo put it on straight lpg then there are very little emission rules you need to pass.Good luck with it