early 273 intake manifold

Offenhauser does a limited run on them every now and then. Other than that, you'll have to find an old one on ebay or something. I think Edelbrock used to make one for it years ago, but not sure. Other options, if you're set on 273 heads, is to find some from a '66. They have the later bolt pattern so you'll have a lot more choices on intakes. Or you could take the '65 heads to a shop and have them re-drilled for the early pattern.