[turnpike boy]

BR, you can probably leave the dizzy right where it is. As long as you can squeeze the manifold out (and it looks like you can), leave that sucker alone.

Once the manifold is off, and the head/header/etc. bolts are out, mop up whatever water spills in with paper towels. Be aware the head will still have some water in it. No big deal. You SHOULD check the rockers after re-assembly, tho - while they might be all right, no reason not to re-check 'em. You won't be able to get the pushrods back in with them tightened down, anyway. An easy task - once pushrods are back in, just turn the crank until you see that both valves on any cylinder are shut, run the nut down until you feel the pushrod is snug and won't spin, turning it with your fingers, and tighten the nut another 1/4 to 1/2 turn. Lock in place there - best way with polylocks is to get to the snug point, turn the lockscrew down lightly touching the top of the stud, and crank the big nut tight that last 1/4+.

You DO have a hydraulic cam, right? Procedure above is for hydraulics - solids are a hair different.