ok, if you want to do a 4agze or something boosted then start with a 4agze, not a 4a or 7afe. if you want to do a 7age then you have to keep it n/a. the FE botom end will no hold up to the abuse of boost. and parts are not interchangable bewteen the FE and GE bottom ends especially the 7a because of the increase in stroke. so either stick with the whole 4agze or do an n/a/ 7age or something similer.