[Patrick Feeley]

In short, you'll have oil drain-back issues causing hard extended starts using a 99 pump on a 95. I can't recall when the later pumps went to a 17 degree design (flows more oil). The IPR will also be different as well as the front cover. See the attached. Cheers!

 

[Patrick Feeley]

If you try to put a later non-checkvalved bodoed HPOP on a 95, it will have drainback issues, causing longer and harder starts. There are some vendors that have higher output (17* or other) pumps using an early HPOP body to alleviate the drainback problem. Cheers!