How much ET will i pickup with following changes

I think you will probably see close to 0.3, but most of that will be due to the trans swap (and some due to the converter). I think you would see a bigger gain if you replace the Air-gap with a Victor.

On my old 410 with a smaller cam (248/254) I picked up ~ 2 tenths swapping from the Air-gap to the Victor. With your combo I think it would definitely like it.