Which spacer for 1965 273

Stumpy said
To cool the carb. Yes. Also I read on the forum that the secondaries don’t fully open with this setup without a spacer.

Gotchya. I will also add I am unsure if the bolt pattern on those early intakes is the same as the later Edelbrock style carburetors and I believe that's what that spacer is for. Maybe someone a little more in the know will chime in on that.