273 Intake Manifold Question!

Maybe this will help. In addition to the Edelbrock manifolds that I listed before, since your 273 is a 1969 any 318 manifold will fit as they are both "small port" heads. In addition most Weiand manifolds that I have seen for smallblock LA engines (which your 273 is) come with small port configuration and then 340/360 guys who care will just open them up to the "big port" size. Weiand makes some great dual plane manifolds like the Stealth and used, they tend to be priced lower than Edelbrock manifolds.. I would recommend that you use a dual plane design for your application and find one with the older style centered thermostat housing.