what do you need to put 351w heads on a 302?

a friend wants to know , and im not sure .

is there anything to worry about from all internals to the springs etc?

Thanks.

 

you will need "stepped" head bolts as the 351w uses larger dia head bolts, on some earlier 302's you must drill the water passages on the head to match the 302's passages with a 5/16 drill bit. Really need to know what year of heads and what year of block........