if i were to build a 261 for myself it would have a Clifford or 4 barrel intake with a 2 barrel adaptor or a small 4 barrel carb of Corse all jetted properly. i see them at swap meets in the 200 - 300 price range. https://cliffordperformance.net/store/ols/products/42-4500wh-chevy-235-intake-manifold