1/4 mile times

Well heres what I have so far...
Suspension,Timing,Carb/fuel pressure.
Gears go a 4.11 or a 4.30
Converter 3000-3500
Planning for new pistons and bigger cam in near future which wont be too much bigger. Maby 545 solid or hydrolic not sure yet.
Also I have the 741 case in my 8-3/4 And i think im switching to either a 489 or 742 from a friend just to go a little stronger. Watcha think?
Im getting new gears anyway so i wanna do it with a stronger center section if i am going to go through it and replace parts... Also will the posi unit from mine go into either of the others????
I know the cars good for 12's as is but the cam,gears,converter is something i wanted to change already anyways for a while now but now its more of a necessety. Watcha guys think????