Since you're pushing the air in, do a mild build 318 and get the combo to work then fix all the errors, then build with a larger engine combo, you will probably save money in the long run.
X2 I have a fresh teen machine shop fresh, with some goodies 2.02 J heads, small cam, its a sacrificial lamb on my 6-71 build, find out what it will not take and then stick a really good forged engine under the 6-71.