Looking for stainless replacement valves for 340

There are more knowledgeable people here that could advise on your best course of action. Iron heads, unknown cam specs, springs etc. If it were me I would look at longer valves, springs to suit, opens doors to a little higher lift cams without possibly having to cut the spring seats, shim the rocker shafts and you're done. I guess:)
Appreciate your input. I realize now I left that info out. I'll add