[Blown353]

There is a good chance your dying problem on hard decel is a result of rich-killing it. Does it belch a big black cloud when you restart it?

This is a typical problem with a blowthrough carb and the milled down choke horn. They also usually mill down the vent tubes too... and the now shortened vent tubes don't resist sloshing as easily and under hard braking you slosh fuel out the secondary bowl vent and drown the engine in fuel. If it really spits out a black cloud when you restart it you can pretty much conclude it's fuel slosh out the vents.

My blowthrough carb had the same issue. Take a really hard stop and it would die, and on restart it would absolutely billow black smoke from all the fuel. I re-extended the bowl vents up to almost the very top of my carb hat and the problem went away.