You don't have to do head work (flow port) but if you do it will only help. Most 440 kits are 11.2:1 compression which means possibly a mixture of race fuel depending on your elevation. I would do the high compression piston with a cam ( if you don't already have one) something that will help even more would be an aftermarket carb. It is not necessary but you will see gains from one.
You might look into doing a 416 kit also ends up being a little cheaper not having to install a sleeve.
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