Think the D4B 4bbl intakes were for the 273s, they have different angled bolt holes.
Can ask @toolmanmike as he has worked with 273s and knows them. Some have re-angled the bolt holes on the LD4B so that they will bolt up to the 273 heads.
Not sure if the newer 302 heads will bolt onto the 273 block? If so then your LD4B intake will bolt right up to those.
The D4B's were for 64 and 65 heads with 5/16" bolts at closer to vertical angles. The LD4B intakes are for 65 and newer 273/318 heads with 3/8" bolts closer to 90° to the intake surface.
