When Ford introduced the all-new 4.6L single overhead cam V-8 in the Lincoln Town Car in 1991, many were underwhelmed. A 281ci cammer in a fat overstuffed Lincoln? Many people saw the new Modular V-8 as an engine that could never be built for performance use, nor could it keep up with the pushrod classics like the small- and big-blocks. It wasn't the end, but instead, the beginning of a new era of powerful low-displacement Ford V-8 screamers leading up to the hot 5.0L Coyote V-8 20 years later.
What most lacked in 1991 was an understanding of Ford's new overhead cam V-8. If you've never been intimately involved with the 4.6L and 5.4L Modular engines, they're intimidating. Pop the cam and front timing cover and the Modular mill is a confusing series of chains, guides, and valvetrain components. It is surely large. Pull the comparatively large SOHC heads and it is smaller than your 5.0L High Output small-block. Though it consumes a lot of space, the Mod' is also long on potential, durability and power.
Before you can build the Modular, you've got to understand the Modular. This is not an engine forgiving of error, even small ones. If you approach this engine sans proper understanding, it gets costly and time consuming. The objective of this article is to help you get it right.
The Modular overhead cam V-8 combines a number of great attributes from past engines. The Modular block is skirted like an old FE or the Y-block; it is cross-bolted like the legendary 427, yet compact like a small-block.
From a more traditional standpoint, the Modular's bore and stroke don't make much sense. The 4.6L is a "square" engine with a 3.552-inch bore and a 3.543-inch stroke configured on 3.937 bore spacing. Take the same 3.552-inch bore and add a little more than one-half inch (0.622-inch) of stroke to 4.165-inches and you have the 5.4L engine. The down side to both Modular engines is the dynamics of these bore/stroke combinations. They do not make good low-end torque. These are engines that like to rev with peak torque coming in higher than traditional Ford V-8s.
When the 4.6L SOHC Modular V-8 was introduced, it was a standalone engine built in one engine plant—Romeo, Michigan—the former Ford Tractor division factory left empty when Ford sold the division to New Holland. In the beginning, the Modular V-8 was simple to understand because there was one plant and one basic 4.6L SOHC engine. The 32-valve 4.6L DOHC came next for 1993 in the Lincoln Mark VIII; also produced at Romeo.
When the Windsor, Ontario engine plant began building the 4.6L and 5.4L SOHC engines in 1996, mostly for trucks and sport utilities, this engine family became more complicated with the two plants generating engines with slightly different architectures. You'll want to be aware of the varied differences among the Modular engines when planning your engine build; Romeo and Windsor engines are different, with minimum interchange of parts.
If you're going to build a 4.6L low-deck engine from scratch, begin with either a new Romeo off-the-shelf block or the 5.0L iron BOSS block (M-6010-BOSS50) from Ford Racing. This BOSS50 block, which is cast at the Cleveland foundry, has the 4.6L deck height and 94mm cylinder bores along with 17mm minimum main web thickness. Main caps are interference fit void of jackscrews and dowels. Though the 4.6L Romeo and Windsor blocks are rugged, this one you can really put to the test. Engine mount bolt patterns are 4.6L iron block style. An adaptor plate is available if you intend to use this block in a 3V aluminum block application. You can lasso the BOSS50 block for about $1,369 plus shipping, handling, and taxes.