8 inch converter questions...

I'm lucky enough to have a 1/4 mile drag strip right on the edge of town, so I get to flog my Duster at the track quite a bit. I've had two goals with this car from the get-go with no power adders or transbrake, I want it to run solidly in the 11s and I want daylight under the front tires.

I have tinkering I'm planning on doing with the suspension yet, which may get me both of these goals, but I want to do something a bit more drastic and change up the combo. It sounds like the 8" converter should be pushing it, but still streetable...though I'll have to weigh it against getting the heads ported.

I had considered the change to a 904, but it'd open a new can of worms, requiring another transmission, converter, and driveshaft, putting me way over what I have to spend. I'd like to, but it's going to cost quite a bit more than I've got.

Anyone have a rough guesstimate on HP gain going from OOTB to ported Edelbrock heads? I'd probably be staying with the 2.02/1.60 valves and however far I can get with around $1000 worth of work.