How much ET will i pickup with following changes

swapping out 727 with tight 4500 flash 8 inch convertor
Swapping in 904 with looser 5200 ish flash 8 inch convertor

Combo is 360
Airgap
950
28 tire
4.10 gear
Moderately ported eddies
1 5/8 Dougs headers
Cam is 260/264 558/558 on a 106 installed 102
Compression is 10.4
Previous best in very good air 11.26 been right around 118-119 mph

Am i crazy to think in the same air i could see 3 tenths. Just guessing the new convertor will be way closer with this big cam and show quite an improvement, then the gain going to the 904.
Car was soft out of the gate. Best ever 60 was 1.58, and on that 11.26 pass.... otherwise 1.61-1.63
Car weighs 3250-3275, will run it onto scale at track after a pass, hopefully tomorrow night if i get a couple of minor things finished up.

Thoughts?