D4b or not to D4b

What are the gains on a 64/65 273 if I swap out to an edelbrock D4B?
Engine is rebuilt with correct 64/65 stock 4bbl intake. Paperwork said it has an "rv" cam.
Car is just going to be a cruiser on weekends and to shows.
View attachment 1715582467
Did you ever do the Intake manifold swap? Offer to buy was removed by staff
Thanks,
Scott

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