Cat exploded, motor is alive, what next

[readymix]

So with the Hedman 69830's I would have to get reducers from the 3" outlet to 2.5" pipe for the Y, then 3" after the Y pipe.

2.25" Appears to be stock for the Y. I just measured it. You don't want the Y to be too big or you will lose a lot of your bottom end, and with a 305, you need all you can get.
EDIT: Use this for the merge. http://store.summitracing.com/partdetail.asp?autofilter=1&part=FLO-Y250300&N=700+115&autoview=sku

 

[BGKYK5]

If your cat exploded, my advice is to stop feeding it pop-rocks and coke.

 

[readymix]

I heard that would add 30 Hp though. Was that a myth?

 

[mr.smartass]

Sweet Jesus the 305 lives? Indestructable!

 

[Slapperbar]

So with the Hedman 69830's I would have to get reducers from the 3" outlet to 2.5" pipe for the Y, then 3" after the Y pipe.

Sounds about right.