318 engine build

im building a 318 right now i did a lot of home work first and still doing more one thing i can tell you for sure is the J heads will drop you compression and thats not good for horsepower from all i have read and talked with people about your better off with the 318 heads they just need a little work most of which you can do yourself with a die grinder and dremal tool like i say im still talking with people so guys if you read this and don't agree please let me know if im talking thru my @#%$%$$&^$ i can use the help as well