Here is a Comp Cams hydraulic you can try, but the nice thing is with a 400 it's hard to find a bad cam. It will work well with an 11" converter in the stall range you listed. Your heads are actually a little large for the street, but not excessive. It should easily put you in the mid to low 13 second range depending on your weight.
http://www.competitionproducts.com/p...umber=12-246-3
If your budget will handle a hydraulic roller, this one should get you in the 12 second zone.
http://www.competitionproducts.com/p...er=CCA12-601-8