Combination change, what would i gain?

I am thankful this nice Cope trick 904 i bought from a member on here( billet drum, A&A brake equipped, yada, yada,...which i dont use) didnt have a low gear set in it. I wont need one. Would be counter productive with squeeze and 4 inch arm.
I am sad i missed on the convertor for this 904, its too loose and has about 12-13%slip in high gear.
Car has yet to run what it did last season with a 727 and one step too tight of a convertor.
Got good air coming, maybe even this Saturday if i can make a footbrake race at Mid- Michigan Motorplex, to try and get this slug at least in the 11 teens.