one say's 8890462 other says 391t201?? no sites match my #s

Welcome aboard - What are you looking for ??

http://www.classictruckshop.com/images/gmhead.gif

mine have the large hump then 391t201 GM27 the other is 8890462 G276 GM14
nothing matches

Um ,that's 3917291 ,just looks like what you posted .
The other is 3990462.

And Vortec heads have like a three toothed "sawtooth" casting marking.

Kinda like this??

___/l_/l_/l_ or maybe this?? __/\_/\_/\_(??).....


And what I call the early to mid '60's 283 Power Pack heads have a large triangle right in the middle of the rect. flat like this..

......___/\___
___l............l___

The earlier latter '50's 283 PP heads are like this if I remember right??

.......__ll_ll__
____l...........l___.

pdq67