This is the engine that you probably know from the Merkur or the SVO Mustang. I have a 1988 Thunderbird Turbocoupe. I probably couldn't go wrong with 10W-30 except that the engine is now considerably modified and will soon be approacing 300 RWHP out of the little 2.3 plus the fact that I want something good for the turbo which is why I'm looking at synthetic. The bottom end is mostly stock but is balanced with a fresh grind on the crank so oil clearances should be tight but I'm getting 50-60 psi on a cold start in the summer(70° ambient) with cheap 20W-50 oil. Once I heat the oil up good it drops to 20-30 psi. This is why I think I need a heavy oil. Plus I drive it like a race car at times. Shifting near the rev limiter, downshifting to 6K and stuff like that and the fact that it's boosted mean I need some incredible stuff in the sump. At first I was only considering Amsoil as I have family members that are dealers and they may cut me a deal. Probably a 15W-40 or 20W-50 amsoil. Then I considered that I can get 15W-50 M1 at work (Advance Auto) and get an employee discount on it. I know these aren't too heavy in our 80-90 degree summers here in VA but in the winter it sometimes gets as low as the teens and I think I may have to mix in some lighter stuff. Is the 15W-50 Mobil 1 safe to start on occasional sub freezing temps? I'm really more concerned about lunching my oil pump drive (aux shaft and distributor gear) which are really weak. As long as I don't see over 60-70 psi at startup it shouldn't stress it too hard. So does the 15W-50 and other such synthetics flow easily enough at say 15 degrees to provide comparable oil pressure to a conventional 20W-50 (which can be quite thick at startup I've heard, and like honey below freezing). Please help me out here and thanks a lot for your help. And what a great site, unfortunately the more I read the more confused I become. But I'm glad there are people out there trying to dispel all the myths that the car and oil companies have started. There should be a slogan "The truth is out there". Thanks, John L.