Does anyone know the size of the pipe going into the converter on an '87 HT4100 FWD? And can i just leave the Air Pipe dangling if theres no cat? Just a little project...:sneaky:

And for an oil change, I used Rotella, GM EOS and Purolator Pure One Filter. I hear the pure one is the best and fram isnt so good. What about the Mobil 1 oil filter, or STP's oil filter, Auto Zone sells all of those...

Anyone?

As Bbob has recommended, only 1 manufacturer actually builds to the GM oil filter spec. AC Delco. Anything else is whatever the oil filter manufacturer felt like at the time. They can change day by day if they want, there is no accountability. With AC Delco, GM has them by the kahonas, so, there is quality control. Believe me, TS-16949 (aka, the new QS-9000) isn't something companies have for fun, it isn't (and it isn't fun!). And AC Delco is, and GM keeps them on their toes.

And for an oil change, I used Rotella, GM EOS and Purolator Pure One Filter. I hear the pure one is the best and fram isnt so good. What about the Mobil 1 oil filter, or STP's oil filter, Auto Zone sells all of those...