Need to identify some bits

[joesvs]

a mate had some v6 cylinder heads and bits sitting around and passed them on to me. i have two sets of heads that are slightly different.
one set has double valve springs.
he thinks that one might be series 2 or off a toyota.
are these interchangable between different models?
are the double alot better than the singles?

also i scored a set of rocker covers that are aluminium, look exactly the same as standard, but have an overflow pipe off one of them. any idea what series they are from??

 

[hinterland]

might need couple of pics for that ask

 

[Doctor Bob]

the alloy covers are series 1 vn, they polish up well too
the heads are probably series 1 as well, hard to say without pics
Rob