One of the most common questions we get regarding the 1996-2004 Mustangs is "What is the difference between Romeo & Windsor motors?", "Which engine had 11 bolt valve covers and which had 13 bolt valve covers?", & "Which engine had 6 bolt cranks & which had 8 bolt cranks?". We walk you through all of the differences of the two blocks and what will work on each motor.
|Cam Gear Style||Bolt On||Pressed On|
|Number Of Valve Cover Bolts||11||13/14|
|Number Of Crank Bolts||6||8|
|Block Stamp Letter||R||W|
|8th Letter Of Vin||W||X|
|Piston Wrist Pin Style||Press Fit||Floating|
The Romeo engine gets it's name from the engine plant it was manufactured in. The Ford Romeo plant is located in Romeo, Michigan and produced the 4.6L motors for Mustangs from 1996-2004 with most being from 1996-1998 & 2001-2004. The Romeo engine can be distinguished from Windsor blocks by looking for a "R" stamp on the block. Most Romeo engines feature a 6 bolt crankshaft and require 6 bolt flywheels. Romeo heads can be distinguished by a 11 bolt valve cover bolt pattern. The Romeo engine also had 10mm hardware compared to the 8mm hardware found on Windsor engines. In most cases, Romeo engines got press fit pistons with powdered metal rods w/ cracked caps. The camshafts on Romeo heads feature a bolt on cam gear as opposed to the pressed on cam gear found in Windsor heads. This makes the timing covers non-interchangeable.
The Windsor engine gets it's name from the engine plant it was manufactured in. The Ford Windsor plant is located in Windsor, Ontario and produced the 4.6L motors for Mustangs from 1999-2001.The Windsor engine can be distinguished from Romeo blocks by looking for a "W" stamp on the block. Most Windsor engines feature an 8 bolt crankshaft and require 8 bolt flywheels. Windsor heads can be distinguished by a 13/14 bolt valve cover bolt pattern. The Windsor engine also had 8mm hardware compared to the 10mm hardware found on Romeo engines. In most cases, Windsor engines got floating pin pistons with powdered metal rods w/ cracked caps.
LMR suggests confirming your engine and VIN number for correlation to ensure your engine is indeed a windsor or romeo.