If you're building a 4.6 SOHC engine, you need to know there are two basic Windsor block castings, and four basic Romeo block castings. It's a good idea to keep Windsor heads with Windsor blocks, and Romeo heads with Romeo blocks to eliminate any confusion in your engine build. If you're going to interchange parts and castings between the two plants, you better know exactly what you're doing or expect all kinds of disappointment, wasted time, and expense.
The Romeo blocks have casting numbers much like our old pushrod V-8 blocks. Expect to see F1AE for 1991, F2VE for 1992, and F4VE for 1994 (there were no F3VE castings in 1993). These early iron blocks were all cross-bolted across four of the five main caps. It can safely be said the F2VE block is identical to the F1AE block. These early Romeo blocks had two-bolt starter provisions. The rest have three-bolt starters. Early F1AE and F2VE blocks had the same bellhousing bolt patterns as the small-block Fords.
A redesigned Romeo block was introduced in 1996 as F65E-CC, F6VE, and F7VE, with five cross-bolted main caps and a knock sensor provision in the valley. Despite the three numbers, these castings are all the same. The "V" in these casting numbers indicates Lincoln. Romeo truck blocks got the "5" that went into the '97 F-150 trucks. What makes the truck block different than the Lincoln block is the oil cooler provision on the left-hand side--one extra bolt hole midblock. There was also an F6AZ-CB Romeo block specifically for the '96-and-up Mustang GT.
The F7AE block was conceived primarily for the '97 F-150 and F-250 pickup trucks. Expect to see it in a lot of other Fords and Mercs of the era, including the Lincoln. There was also a F7VE block, which was more Lincoln specific. Expect to see it in a variety of Ford applications. In 1999, Ford began producing the XW7E block, which allowed for relocation of the oil filter to the rear of the engine away from the cross member.
Another important issue to remember is the cross-bolted main caps. Early 4.6 engines had torque-to-yield cross-bolts--also known as jackscrews--that pulled the main caps tight to the block's side skirts. About 1996, the jackscrew-style cross-bolts were dropped in favor of precision spacers/dowels and conventional bolts.
The Windsor foundry and engine plant first began producing Modular V-8 engines in 1996. In your search for a block, you're likely going to see similar casting numbers between Romeo and Windsor, but similar numbers do not mean similar castings. Those first Windsor block castings are numbered F65E-BB and F75E for the '97-'98 F-150 and F-250 trucks. That is the significance of the "5" in the number. The F65E-CC Romeo block, though a truck block, will not interchange with the F65E-BB Windsor block. All five main caps in the F65E-BB and F75E blocks are cross-bolted. What makes the Windsor block different than the Romeo block are the dowels between the main caps and the block instead of the jackscrews used at Romeo. Windsor blocks typically have a "W" logo on them somewhere, location varies.
The 5.4 block (F75Z) is similar to the 4.6 block, except for deck height. It is a taller block, just like the 351W is taller than the 289/302 block. The 5.4 deck is 10.079 inches instead of the 4.6's 8.937 inches. Because the 5.4 SOHC had its share of problems early in the going, Ford revised the block in 2001, using more iron to improve reliability.
Down under, we see the lean-looking, short crankshaft safely secured by five cross-bolted
With these iron-block SOHC engines, expect a cylinder wall thickness of .110-inch thickness on the thrust sides of the wall and .165 inch on the fore and aft sides. This means you can bore the 4.6 and 5.4 engines .030-inch oversize. We strongly advise against a larger overbore.
According to Sean Hyland's book, 4.6-Liter Ford Engines, Teksid of Italy, a supplier to Ferrari, cast those first aluminum blocks. This remains the strongest 4.6 DOHC block available. according to Hyland, these blocks received special treatment. They were cast in SAE 319-modified aluminum alloy, heat treated, and aged for strength.
Beginning in 1999, the Windsor Aluminum Plant (WAP) entered the production picture, producing the 32-valve (DOHC) blocks. Ford beefed up the 4.6 DOHC block, giving it extra ribbing for both strength and quiet operation. The pan rail was also thicker for both strength and reduced noise and vibration. Although the extra ribbing may look impressive, it's there because there is less aluminum in the casting. Keep in mind, this doesn't always make it a better block. The best block to use is the earlier Teksid casting (prior to 1999) if you're going to be doing some serious racing. The Teksid block casting can stand up to 900 hp, according to Hyland. He also says the Windsor aluminum block can take up to 600 hp.
Although we tend to think of the 4.6 DOHC engine as a rear-drive engine, Ford used it in a front-drive application in the Lincoln Continental. The front-drive Continental employed a different block than the rear-drives, with different bosses for the mounts and a different bellhousing bolt pattern. It will not fit in your rear-drive Ford or Merc.
Because the 4.6 DOHC engine is all-aluminum, it is fitted with ductile iron cylinder sleeves. The best thing about this design is being able to swap these sleeves (liners) as the need warrants. Granted, it is not an easy process, and best left to a professional, but it is a great way to salvage a block. Ductile iron and aluminum alloy cylinder sleeves are available from the aftermarket. With these cylinder sleeves, you can up the displacement to over 300 ci. Mix in some stroke from one of the aftermarket stroker kits, and you have real power from your 4.6 DOHC.