I have 238/100s, zf6, 3.73s, and a 366sxe with a 1.0 housing. Super quick spool up, great top end. 1:1 boost:back pressure up to 40 psi. I wouldn't change a thing in my setup. Perfect towing machine too. I DD My second hottest file, and only put it in the highest for being dumb. My second hottest file will not exceed 1200* in any situation.