Valve Spring Recommendation

In many cases, springs that fit factory heads aren’t a great fit on the aftermarket replacements.
In the case of the SBM Ede heads, they’re set up for a nominal 1.800” IH, while the factory heads are 1.650-1.700”.

I’d leave the as supplied springs in place for this application.
340 HP's would probably be lucky to have 50# on the seat on those heads, lol....