Technical 331 Cadillac engine build , looking for insight

Late 331s have the same block as the 365-390s I believe.
Should be fine.

 

Can anyone tell me what my valve cover options are ?
My motor is a 1955 331 but it’s running 390 heads . I really like the Cadillac script valve covers ( like in the pic ) but wasn’t sure if they weren’t usable cuz of the 390 heads. Thanks !

 

Should fit fine, mid to late 49 all the way through to 61 390s are the same 4 bolt pattern, if standard rocker gear is used.
The first 49s for 3-4 months are 2 centre bolt rocker covers.
Happy to be corrected if I’m wrong.

 

The early style script showed up on the regular bolt pattern in 55 I believe. The later 365’s and 390’s have a block letter, which is ok, but not as desirable. I’m not sure on the years, that was a wag.