Hey guys I have a built up 331 stroker in a fox body Mustang that makes pretty good power for its size and see frequent 7k rpm shifts. I was debating trying either Mobil 1 15w50 or Pennzoil Euro 5W40. The local engine builder is a Ford nut and although he didnt build the engine he says he always recommends regular 10w30 and never synthetic because all it does is burn in these motors. I had Pennzoil Platinum high mileage 10w30 in it for a little while but I started to notice some blue smoke. I really dont think it being synthetic has anything to do with it burning. So do I step it up to 15w50 or do I try like 10W30 VR1 non synthetic? My only concern with thick oil is snapping an oil pump shaft at high rpm since its got a high volume oil pump and constantly see around 60/70 psi unless its at idle. Currently it has Mobil 1 10W40 high mileage and there is no smoke but Im worried about the oil thinning out.