VINTAGE ROAD RACING QUESTION

Greetings!
While still in the midst of restoring my 67 Dart Ive decided to point the resto towards some SVRA racing. Being that the 273 was the biggest offering for the Dart in 67 I need to source one to replace my slant six. Will it have to be correctly 67 date coded or can it be any pre-1972 block? The rule sheet isn’t clear and I’m a novice so any vintage racers out there?
Your help would be appreciated.
Thanks,
Troub

Need to talk to that region SVRA. And go to races and talk to guys racing.

They might allow a 67 to have 1970 rules. And that would allow non-production 5.0 liter limits (302)