408/ 904 trans

Thinking of replacing the 727 with a cope 904 simply for the E.T gains
But a little concerned about the low first gear
Will it still help with a stroker
I have 456 in the Dana with a 28 inch
Almost feel like I may be using to much reduction when coupled with the low first gear with the 904
Any insight would be appreciated
Thanks guys
Engine
Basic 408
Should make 560-590hp