Need help and advice (Intake and carb swap)

Good mention quick!
IMO, Take out the dowel pins, do not drill the intake. That'd be silly. The gaskets are sometimes ill cut or outright wrong.

Reminds me of a time when doing a freinds intake, the end seals were cut 3 inchs longer than the block was wide. Go figure! LOL

Anyways, often MoPar sez skip the end seals in favor of a large beed of sealent instead.