Classic/Antique Car Repair: engine valves, good luck jack, 31 ford

Question
Dear Jack, I'm about to pull head and renew valves and guides on my '31 Ford pickup. I want to know why there is a choice between original type valves with split guides and the "modern style" valves and one piece guides. They're both made of stainless steel but the new type are more than twice the cost! Am I missing something here?? Thanks for your input , Pete.

Answer
I did not know the prices.  If that is the case, go with the old original.  There is nothing wrong with them.  The old ones cost about $110 and the modern cost about $135.  Now, what am I missing.  ($57 valves+ $53 for guides, Old style)  Assuming that you do need new guides.  If your old guides are OK, then just put in new valves.  You may have the new style in there already.  I found the new ones in my engine.  
I recommend you keep whatever kind you find when you take it apart.  
Good luck.
jack