What are the D20E heads?

[Boss 351]

I found a set of heads with the casting number D20E, do any of you know what these are? Are they any good?

 

[rd]

From the number they should be 1972 heads.

Good stock heads for a regular 302. Probably have large chambers, and pressed in studs for rail rockers.

 

[Boss 351]

Thanks and they're closed chambers? So they would be better than stock? I might dump these in my dad's 302