Hmmm....people underestimate the power of the SEARCH button. Hit that search button and just type in "351w swap" and you will get a ***** load of threads about it with all kinds of good information. You will even get threads like this one tellng people to search....
BUT ANYWAY, since im bored and am thinking about this swap also, i will tell you what i remember off the top of my head. You will need a distributor(from a lightning or aftermarket i believe), an oil pan, battery tray knotched or battery moved to trunk, depending on your upper intake you might need the drop motor mounts for a Trickflow intake to clear a 3inch cowl hood. I think that just about covers the conversion from the 302 to the 351.
Other parts come into play cause it depends on the 351 motor u get. If its roller or not, what kind of power you want? Are you stroking it? New injectors will probably be on the To Buy list. A decent pair of heads and the intake to go along with a new cam.
Its really not that bad when u think about it and compare it to building up a 302. Yes there are more parts to buy but its not anything extreme. The more parts you have on your 302 that will swap over, the easier and cheaper your swap will be.
oil pan
28 ounce balancer
351 lower intake form the company of your choice.
an aftermarket hood
a lightning distributor
accessory brackets
spacer for crank pulley.
fly wheel
351 headers
longer serpentine belt
must extend the tube between the fuel rails
30#+ injectors
heads
cam
shortblock
all the bolts and gaskets
they sell dropped motor mounts 3/4"