318 garage clear rebuild

Yes of course, till now its all just ideas.. have not even opened the 318 yet hope it needs no bore

Is there no information about how much the original pistons should be in the block? And how much cc do the 1969 318 heads have about?

If they are 675 heads they should be about 68 cc. You still need to check to be sure. Who knows what they did for exports.