Its just been run hard without a series of good oil changes.

Attention needs to be paid to the end float and thrust bearing. When the factory Toyo Kogyo 5 speeds were used, the engine, which was born as a dedicated automatic engine from 1982 to 1988, had some issues to deal with having a center punch throwout bearing. When you use the T5, you'll have to be certain you use the right 28.2 oz unbalance flywheel, indexed correctly. I'm pretty sure the 4.2 kept 28.2, although I have heard that there is a 32.2/ 39 ounce unblance split with one later version. A full rebuild is best when you change the transmission type on a four main bearing even fire V6.

I'd check a little more on the over bore and crank bearing type options


Now, how I feel about all this....at an opinion level, untendered....

The MN12 3.8 was the rebirth of the Roots blower...without it, Buick wouldn't have followed suit with its GM3800.


The E-90 V6, the Eaton M90 blower, its all American as, even if it was Ford USA first metric OHV V6 engine design, and built in Canada....

Gotta love it.



I started off with GM in line sixes, 4 cylinder Pinto engined Fords and 351C Falcons, so an Essex 90 is halfway in between.

About 1988, after a 375 hp Cleveland build up with a brilliant Engineer called Blair, I found Vizard books and Supercharging. Between marriage and financial growth with three kids, I got into A series and B series Limey in line fours (Mini, Morris Marina) in line sixes and V6 Fords, and never went back to Bent Eights.

For me, Léon Levavasseur invented it, but Henry Ford re-invented the V8. Craig-Dörwald and then Packard made the first production V12's, but Enzo Ferrari re-invented the V12.

For me, despite the statements that Dugald Clerk devised the first supercharged engine in a two stroke format in 1875, it was the Roots Blower Company of Connersville, Indiana, c.1860, that made the first functioning Supercharger, and in 1900, Gottlieb Daimler included a Roots-style blower in a patented Supercharged Otto engine design.

As far as I am concerned, Benson Ford rebirthed the centrifugal supercharger with the McCulloch/Paxton blower in 1955-1956.

Others say it may have been Graham Paige who sold the pants off them from 1937-39, but its was putting them on a 312 Y block which tipped the AMA Ban of Superchargers, and Shelby re-kicked it again in 1965 to 1968.

The Roots blower had the war winning GMC 3, 4 and 6 71's to thank, and Barney Navarro's 3/71 blown flattie mixed the rebirth V8 with the re-birthed Roots.

All this makes the MN12 engine a prefect edition to the Model T like Fox Mustang.

Do your research, ask questions, and go for it. You won't kill that four bearing V6!