5U4 vs 5V4

My Cary 2A3i integrated has a pair of RCA 5V4 rectifiers in it and sounds fine. The manual calls for 5U4s. Are these truely interchangeable, and if not, then what is the impact from running the "wrong" rectifier. I will try and contact Cary tomorrow. TIA
Yes,tube pinouts are the same. The 5U4 has higher [MAXIMUM RATINGS].The 5U4 will cost more to buy, than the5V4.The 5U4,5U4B,5U4GB,Email CARY for there rec.
Thanks, Jea48.