1965 273 2 bbl engine.

Take a while to consider your options. Occasionally, you can find a 4 bbl aluminum intake that fits the 64-65 small block heads (Edelbrock LD4?, search posts). Indeed, one guy here had one and wanted to adapt it to a 66+ engine. I told him better to sell to someone who needs it. I have also seen them sell for ~$150 on ebay. That intake may have a different bolt pattern which fits the original 4 bbl Carter carb (small square bore?) and may need an adapter plate for later 4 bbl patterns (read up).

One option is to install a later intake. I put an Edelbrock Performer 318-360 on mine. I drilled countersink V's in the bolt holes with a hand drill (a bit squirrely) and used 7/16" flat-head allen screws. Not ideal. I couldn't torque the screws as much as I wanted and the allen holes are so small I am afraid they might strip when I try to remove someday. I got a little steam hissing from a front cross-over port at first, but re-torqued while hot and seems to have stopped. Maybe hex bolts and washers and studs & nuts would work better.

Another option is to change heads, as mentioned. If you install Magnum heads, the Magnum intake gets you MPFI, if that is your eventual plan. I read that those heads have a big problem with cracks between the intake and exhaust ports. One guy found 3 of 4 junkyard heads cracked. Some heads require slight grinding of a tab to get 65 exhaust manifolds to fit (search posts).

My long-term plan is to put a Magnum intake on my 65 heads to get cheap MPFI. One guy said, "why not just install a whole Magnum motor?". I lost how that is easier than an intake swap. I know about the bolt angle difference and have a plan, but don't want to lead you astray.