Since he is an '08, maybe that is as big as he is ever going to get.
I have a pair of '08 Pacifics and the male is 610 grams and his mate is 450 grams last month out of brumation. I expect some increase in growth this year but not like when they were younger. Then I have an '08 Pacific female not related to that pair who weighed in at a hefty 1314 grams this February. And a little male San Diego '10? (wc) male although very healthy weighed only 284 grams. Lastly a striped Pacific female '09 who weighed 406 grams. Since they have all been eating well recently I expect they are all heavier now.

My point being there seems to be a wide range of weights amongst these pituophis but as long as they are healthy and not too thin I don't worry.
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Bob
Pyromaniac AKA Greatballzofire
Keeping cats allows man to cohabitate with tigers. Keeping reptiles allows man to cohabitate with dinosaurs.