To sum up for the OP your turbo is too big and what ever you do,if you keep the 45a,don't switch to a bigger exhaust housing. What,he kept the 45a and switched to a bigger exhaust housing? Well,at least he'll never blow a head gasket. Of course,he'll never be able to leave on anyone either,but his exhaust housing will be much cooler when he checks it after a run. Quick,get out and point this at my turbine housing. Oh,I almost forgot,we need to do something to lower cylinder pressures. I suppose that would also help reduce the possibility of blowing head gaskets. See that guy over there? He's never blown a head gasket. Is that why all of those hot blonds are always hanging out by him?