This depends on the deck height of the pistons you have. Someone please correct me if I'm wrong, but I believe the only reason Edelbrock makes the 340 specific head is to clear the stock 340 high compression pistons. They stuck out of the hole a bit to raise the compression on the open chamber heads. There would be clearance issues if you slap a set of 360 Edelbrock heads on with those pistons. But if you rebuilt with flat top pistons, you should be okay with the 360 heads.
