I'm planning on replacing my old single plane TM6 intake with an Edelbrock performer RPM dual plane on my 383. When replacing the gaskets, do they go between the valley pan end heads, or between the intake and valley pan? OR both? I've replaced a few LONG ago in 340's, but the big blocks are obviously different. Also, will I need to drain the coolant? Dont know of any water jackets, but want to be sure before I begin. Dont need any surprises and do-overs.. lol Thanks in advance.