I have registered a couple of imported motorcycles, both of which came from the USA. I can't see the procedure being any different to registering a car, and your car won't need an SVA test because it is too old. (SVA is for new or nearly new vehicles). All you should need is the following:
1, Proof of age certificate - This can be obtained from a
recognised car club, and will probably cost you about £20. AROC may be able to do this, or maybe even Alfa OC. DVLA can advise if you can't find a club able to do this.
2, Form V55, available from the DVLA. (They will post one to you if you ask).
3, An MOT. You can legally drive your car to a testing station without a number plate providing it is booked in for the test against the chassis number.
4, Valid insurance certificate.
5, A cheque for the cost of the road tax
plus the registration fee of about £40. (It was £38 when I did it two years ago).
Bear in mind that you may have to present the vehicle to your local DVLA office for verification, but this is not always necessary since the only tend to have random sample inspections. Another point worth mentioning is that a more rural office may be easier for you because of parking facilities (the DVLA call centre told me this, and they were very helpful), so if you have a choice, post your documents to where you will take the car if you have to.
You cannot register the car without taxing it at the same time.
Once the forms have been received by the DVLA, you will get a tax disc back by return post and a V5C within a couple of weeks.
