[Philip Saran]

As Jim and Myron have pointed out keep reading the rule book.

You have mentioned that your bracket car runs 11:60 on just the
primaries (no secondaries) is this the 318 motor you are thinking
of running in stock?

Read the rule book and check the NHRA website for the engine
specs to see what valve size is allowed, cam lift/duration, what pistons
and rods are legal for the class you want to run.

Also keep in mind that 360 parts are (resonably) dirt cheap and it is
42 more cubic inches and allows a 4 bbl carb.

Good luck with your project.