What RPM going through the traps with a 408?

Man we think alot alike ,as i just added a 1 inch spacer and jetted up my 408 for the same reason.Only difference is im only in the 11.40's.I am running 4.10's in the 1/4 with a 26 tall slick and im going through the lights at 6200-6300 at 113.5 mph.My stroker seems to fall off after about 5800 rpm sharply (i dont have enough cam).On the other hand im in the the mid 7.2's in the 1/8 with the 4.86 gears.I havent ran it in the 1/4 since the spacer and jett upgrade ,but im thinking it should go a real high 11.3 or real low 11.4 in the 1/4 now when i switch the gears back to the 4.10's.I wont know for a few months though.I can tell you that the spacer and jett change moved the powerband up a few 100 rpms in the 1/8.It used to break up in the lights at 6200 ,but the spacer and jetts fixed it .I want to run 10's bad also .My major obsticle is the Powerglide trans.I want to keep it because its built and has a Tbrake and a pricey convertor ,plus its holding up well to my low 1.5 60 foots.It needs 3.91's in the 1/4 IMO ,but it will cost me 60' with the high ratio first gear it has.My 408 is only 10 to 1 and has a hydraulic .484 /235 duration cam in it with a 750 Demon.Your closer to the 10's than i am for what its worth ...