Thoughts on exhaust housing size for a twin 66mm 347? I was shifting my old combo at around 6600 rpm with my 331 and single 76mm turbo. I currently have two Turbonetics 66mm turbos rated at approximately 750 hp each. The turbos came with .68 housings. I'm worried that the .68 housings might limit my shift point. Any experience with this? I'll try them and if it won't rev, I'll get .81 housings next year I suppose. I'm shooting for 1000 rwhp through my TH400 and 8 second 1/4 mile times with this combo.