351 heads

Im rebuilding my 68 coupe's 289 small block and I would like to bring the power up a bit. I would like to put better flowing heads on it, but aftermarket is way out of my budget. I have read a lot about gt-40 and gt-40p heads as well as 351 heads being decent options for the small block...

I have a 302 that im dropin in my 1985 ford ranger im want to put a set of 351 heads on them, but everything im seeing online says i have to get a special bolt set because te 302 have 7/16 bolt holes and the 351 has 1/2, but the head to block pins keep them in place so do i have to get new bolts...