The 3.9 V-8 in our T-Birds is a Jaguar V-8 design. Its already ported, etc., with 4 valves per cylinder and is a very bullet proof and efficient engine design.
The 4.0 is a cousin and later gen motor. These v-8's are known around the world as they have been put in many Land Rover SUV's and other expensive cars.
As far as the oil goes. I'm sure the
Motorcraft semisynthetic is a great oil, but there are better oils to use in the engine. I watch a blog by an oil engineer, his name on the web is RAT540, who does independent friction tests on a multitude of oils at normal temp of 230 degrees and close to where most oils break down at 275 degrees, then rates the oils in his blog. His test establishes when a piece of test metal rubs through the oil film against another metal, like in our bearings to the crankshaft, for example, or a cam follower to the cam lobe.
Mobil 1 does very well at the 230 degree temp, but falls way off into the good category if the oil is hotter. Since I do not know how hot our oils run, knowing they are using 6 quarts oil in a small engine but in a very confined engine bay, I presume on the warmer side. So I error on the side of using the best oil possible and change usually once a year.
Go google RAT540 and read his 100+ page report.
Reading it a month ago, Quaker State Ultimate Durability 0-20 full synthetic was a much better performer, up there with Amsoil but under $19.00 for 5 quarts at Walmart. There are others we see at Walmart or the auto
parts store like Pennzoil, that are in the exceptional protection category, and those are the oils I am interested in using in all my vehicles.
