340 cam

Howard's cams has a nice 340 replacement cam. I forgot the lift but the duration is 267* / 277*. Performance cams, the ivc gets later like 65* and more. Like you said, compression ratio has to be know or you could bleed off to much cylinder pressure
Got the link to the Howard’s cam?
Listing advertised duration doesn’t really help that much. Knowing the over lap amount does.