<VV> valve covers

[Robert Brought]

Someone told me a few years back that there was a meaningful  
difference between early (145cid) and late( 164 cid) valve covers.  I  
have compared and measured and can find no difference, other than the  
obvious that the lates are clearly better looking:).  Anyone know for  
sure if there is a difference and what it might be??

Bob Brought
3 FC's
2 4 doors
3 coupes
1 convert