i have a 73 dart sport that has been lightened a great deal,but no fiberglass yet.all said and done with me in it im hoping for 3000lbs.id like alot of street miles and performance handling and do some open track roadcourse days.it may go to the drag strip a few times but no slicks.

rear end right now is 8 1/4 open 3.55 but if need be i have an 8 3/4 pumpkin 3.23 and can gat a housing for free

engine is
.030 383 /906 heads,hardened seats,big springs,light port work
street hemi lobes reground on cam core from delta
stock rebuilder cast pistons
1 3/4 headers,no exhst yet
action plus intake
choice of lots of carbs-eventually e85

so there is a big block 727 tranny behind it whos history is a mystery-looks rebuilt not long ago and doesnt smell burnt-i have a backup big block stock tranny as well

i was thinking i could sell the big block cores and use my stock driveshaft (this will save about $150)and put 904 behind itwith a jw ultrabell and it may not cost me anything

pros:
904s are way easier to find than big block trannies
less drag?how much?
lighter?how much?
some times low gear set
maybe one day swap in an a518
a little more engine setback

negs:
strength
which 904 to use?999,904,v8,slant six-are any stronger than the rest?