I recently swapped a 88' b230ft long block into my 86' 740 turbo. I've re used the intake and exhaust manifold/turbo from the old motor, and now I'm running into some peculiar issues. The cam timing is dead on, the ignition timing is dead on at 12 degrees BTDC. But the car is not running quite hot, specifically the turbo side. Coolant temps are at a healthy 200 degrees, but the exhaust manifold and eventually the turbo get cherry red after driving very conservatively for 5 minutes or more. I'm assuming my problem is coming from a lean afr? The motor runs awesome, makes all kinds of cool choochoo noises, and the car is quite fast now, but something is not right. I've checked for vacuum leaks, replaced the injectors and fuel pressure regulator, and now I'm scratching my head. I've tried driving with the o2 sensor disconnected but it makes no difference. The coolant temp sensor for the ecu is less than a year old so I've ruled that out. Has anyone else had this issue? I am assuming I've mixed up a sensor or something stupid like that. any help is appreciated. Thanks turbo nerds