The Olds linkage can be set for 30 or 40 deg. opening position for the secondaries. As noted above, all Tri Carbs were stick cars and all used ported vacuum from the fuel bowl of the center carb. I've been using Tri Carbs for 35 years. In the mid-70s I compared properly jetted Tri Carbs against the 800 Holley and Edelbrock Torker. The ancient, cast iron lump from Olds with those sorry little 2 jets ran 1-2 tenths better in the quarter
