Check out my 2015 thread on
https://geometroforum.com/viewtopic.php?p=274701#p274701
CBC2 POWERKOTE heat coating
and Tech Line DFL-1 for bearings and cam

It still gets 52 mpg at 70 on a level highway.
28 years old and no one has made a more economical car since.

My 5.7 1997 RAM wagon gets 16 hwy at 70