iamdub
Full Access Member
If I remember correctly Purolator makes the Motorcraft filters to Ford specs.
I strongly question and often disagree with a number of GM's specs. This leads me to question other manufacturer's specs as well, especially when a third party is involved as the specs could be biased/bought by contracts between companies.
Although, I strongly adhere to GM's LS engine build specs. It's a proven design and actually kinda fun hitting their numbers.