OK. Well I went and looked at the NA and the TB has a different setup! The SRT has a different attachment with a spacer that is rubber coated to seal the TB to the SC housing. The TB on the NA goes directaly to the manifold and is “upside down” with the hose on top, I guess the O-ring is only for the NA! So should I try to put the 78mm on a NA, that will be a big jump from stock.
I've never known anyone going past 74 mm on an NA, kinda on yer own there.