Dave
It's been I while since I rebuilt a flat head buy the Compressor clamp that Bob Carrier is talking about just hold the top of the valve down and compresses the spring..Once the spring is compressed the "Tabs',which if I remember correctly are little half round tapered wedges that fall out once the spring is compressed...
THen the spring and retainer washer comes out and the valve can be pulled up out of the block,and then the guide can be smacked out with a drift..
I'm going by memory but I don't remember it being a tough job..but I did have the right valve spring compressor..
Doing the valves with a lap stick and adjusting the clearances by grinding the end of the stem is something you want to be sober for...
