Aussie returning to Canada with a problem

Hi, I'm new to this.
I immigrated to Canada way back in the early 70s. Had a Social Security number and all that. I did contract work for which I was registered as a company (1 man). Didn't earn much, back then it was about $6.25 per hour. I was there for about 2 years and worked for about 18 months. My problem is that I would like to return as a tourist. I 'forgot' to pay tax whilst I was there. Should I be concerned? Would those old records be computerized? What are Canadian prisons like?
Sensible advise would be appreciated.

If you were here in the 70's and didn't pay your taxes back then I would definitely NOT come to Canada. You're nuts. Our tax enforcement rules are CRAZY, they catch people right at the airport and take them directly to maximum security prison.

NOT!

Don't worry about it, get your tourist visa and come to Canada... the authorities don't check whether you owe taxes when you come for a visit. In fact when you apply for your tourist visa, since you're travelling on your Aussie passport (I assume?) they definitely won't connect the dots. Relax, come enjoy Canada for a trip. I recommend July/August.