I think in order to brake boost of off the line you need to have a high stall TQ converter. I'm not sure tho don't know much about AT.

And the AT's have 390cc injectors, also I don't know if I missed it but AT's have the 13g.
If you want I'll sell you my 450's cheap. PM me if your interested.

EDIT: I guess you do have a 14b since you were talking about porting one and putting the stocker back on.