Accufab/BAE’s Billet 5.0 Block

The king of the modular motors has teamed up with the baron of Hemi billet blocks, to launch a new 5.0L Coyote Motor that is cut from one solid 600-pound chunk of aluminum and can easily handle over 3500 horsepower. 

The impetus for offering a 5.0L coyote billet block according to Accufab’s head, John Mihovetz, was that the stock factory blocks were cracking in high horsepower racing applications. “Basically… the issue with the block, specific to racing at the level that we want to race, the block is hard in many places, but hard in this situation is brittle. It can go a certain point, but its easily broken, and that’s what I kept hearing from everyone in the racing circles that were doing it.” 

Some have tried to fortify the block by filling the water passages with concrete, but according to Mihovetz, filling it would make the block solid, but the aluminum would still crack, “it’s not going to leak any water, but it is still structurally unsound.” 

Sleeving the cast block was also inadequate because “you can’t put enough press fit on it to retain the sleeve properly or the block will crack,” he says.

The coyote block, according to Mihovetz, “has improved over time… but basically from the factory standpoint it does what it was designed to do, the fact that it can’t make 2000-3000hp, really wasn’t a factory design flaw—it just wasn’t made for that.” 

However, Mihovetz who’s long list of successes includes: being the first person to get a mod motor into the 5-second zone in the quarter-mile; and being the engine builder of the first car ever, in history, to break the 300-mph barrier in the standing mile, said that the only way that he would enter into competition with a coyote powered engine was if the rigid block issues had been fixed. The only solution was to build an all-aluminum billet block that would replace the factory cast unit. 

At the end of 2015, Mihovetz decided to go forward and build a block. He bought a new CNC machine large enough to mill the aluminum, but Accufab’s acquisition of Lenco Transmissions put the engine project on hold. When he re-started the program, he decided to ally with Brad Anderson Enterprises (BAE).

this block starts out at 16 inches thick.

“I decided to partner up with Brad Anderson,” says Mihovetz, “with all things considered, who could you find better that makes billet blocks than those guys? They’ve literally made thousands of Hemi blocks over the last 30 years, so it was a natural deal, to pick the best guy in terms of making modular stuff and the best guy making blocks and put them together.”  

Both men created a mandate, that a possible product had to be the best if it were to have their names on it. What they came up with was a block that is made with different manufacturing processes than anything currently in the Mustang market, and one that introduces new innovations. 

The new Accufab/BAE coyote block starts out as a 600-pound chunk of 6061-T6 aluminum that measures 16”x18”x22”. The difference in manufacturing is a three-step process of rough machining, heat treating, and then finishing machining. 

First, the bare material is rough machined into the overall shape of the 5.0L block. It is then heat-treated to cure it. Mihovetz explains that a material cannot be guaranteed for core hardness, from the manufacturer, if any portion of it is thicker than three inches, and “this block starts out at 16 inches thick, so effectively speaking, the core hardness of the block, without it being heat-treated, is not going to be a uniform hardness.”

If the block was not heat-treated, it will move as it heat cycles during normal operation, “machined [without heat treatment], describes Mihovetz, “everything in the block moves. The block is consistently trying to get itself to a T6 condition, and through the heat generated by running the motor it changes the structure of the motor, [and] that’s why all our blocks are rough machined, heat-treated, and then finished machined, so it’s not going to move later, and that is the same process that Brad Anderson has done with all of their Hemis for the last 30 years.” 

the same process that Brad Anderson has done with all of their Hemis for the last 30 years

It is a dry block. It was designed with no water passages for cooling. Mihovetz points out that this was because it is for drag race-specific applications. He also says that “making a wet block is going to be a pretty big challenge—you can’t have a piece of sheet metal and weld it in the valley of the engine, and call that a wet block because you need to have equal water all around the cylinder for it to work properly.” Mihovetz is clear, “[It’s] not for the street.”

The Accufab/BAE Coyote Block has a normal deck height. They did investigate offering a tall deck variant, where the cylinder deck height has been increased to allow for a longer stroke, but Mihovetz does not see the benefits of a stroker motor. “We looked at doing one, but mechanically it’s not a sound piece,” he says, “if the stroke is too long, and the bore is too small, you can’t get the proper rod ratio in that motor.” So, the Accufab/BAE block has the same deck height as the factory Ford unit. 

They started with a clean sheet a paper, and other than the obvious things like the crank and piston locations, they were able to build the block that they wanted. Mihovetz recounts that they looked at what was right and wrong with the factory block, while also documenting what was already available in the aftermarket, and how they could “introduce new features to the platform to make it better.”

The first innovation was the introduction of a communication port. “One of the neat things that we were able to do at Brad Anderson’s was to create a communication tunnel through the block. One of the things that a lot of the mod motors suffer from is poor communication or no communication—The 5.4L GT500 block [and] 5.4L GT block had no communication,” says Mihovetz, and “that was one thing that is suffered from in comparison to the smaller 4.6L stuff.” He also claims that “the blocks that were on the market right now had no communication.”

The benefit of the port, at these horsepower levels, is to alleviate piston blow-by. With high compression and high boost levels, significant blow-by is a natural byproduct according to Mihovetz. “The importance of the communication tunnel is you have to have a place within each bulkhead to displace that volume of air.” 

One of the neat things that we were able to do at Brad Anderson’s was to create a communication tunnel through the block.

Accufab made the communication port length of the entire block and it could be used as “a scavenge section from a dry sump,” where a customer could “pull out any vapor that’s trapped behind any rings in the pistons,” he says. 

Another innovation was how they dealt with the oil management. Mihovetz points out that because the coyote has a hydraulic valvetrain, oil quality is very important. It is essential to do everything possible to manage the oil, control how it gets back to the pan, and prevent it from aerating. These are all crucial factors when a motor is reaching high rpm.

They addressed the oil management by both minimizing oil where they could, and by maximizing the oil’s ability to drain back into the pan, “keeping it away from the crankshaft,” says Mihovetz. “We extended the oil drain backs from the cylinder heads, all the way to the oil pan. In doing that, we can actually seal the drain backs into the dry sump pan, and the oil coming from the cylinder heads, which is quite a lot, basically it never gets into the crankcase, so were not creating windage in that regard.”

Despite not being a fan of stroker motors, Mihovetz knows that customers still may want to run a stroker setup, so they made sure that the block is stroker ready. The block has a “radius—arch in the center of the block,” he says. “We bulge the block out in the middle, at the parting line where the crankshaft goes in, to create more space around the crankshaft—to create better space for the oil to return around the pan without being caught in windage, and so a guy could run a stroker crank or rods, and not have to grind or do any type of modifications to the block.”

One change that Accufab made was more of a convenience modification, it was an alteration to the factory pressed in pins that have been an annoyance to many who were building a coyote motor. “When you get a block from the factory, it’s already pressed in. I’ve seen many of these blocks come in from shipping and the pins are hanging outside of the freight box—[They’re] easy to damage, and particularly in that regard to break the block if the guy hits it in a forklift,” says Mihovetz. 

We extended the oil drain backs from the cylinder heads, all the way to the oil pan.

With the Accufab/BAE block, the pins are screwed in and can be removed easily when pulling an engine out, or when transporting it to the engine shop. 

Aluminum rods are a no-go, as Mihovetz expresses that this motor was not made to be used with aluminum rods. “If the bore is too small you can’t use an aluminum rod of substance that’s going to fit, so it just doesn’t work,” he claims, “We led the way with our 4.6L [engine] for many—many years and we never had an aluminum rod in any of those motors. We ran it 10,400 rpm. There’s no solid argument for anything other than a steel rod in these motors—It’s not made for aluminum rods, and I’m not going to sell on to someone who tells me that they’re going to use aluminum rods.”

The block is made to handle 3.800” stroke crankshaft. It “has longer sleeves to support the pistons at bottom dead center,” says Mihovetz, while still having the proper clearance so that a consumer doesn’t have to notch the block. 

The sleeves require honing by an engine shop. They are five-thousandths of an inch undersized. 

The head studs are oversized and are the same units that BAE uses for their Hemi blocks.

It is designed for current Gen. 3 coyote cylinder heads and GT350 heads, which are the current top-performing Ford cylinder head on the market. Although, they will fit older generation coyote cylinder heads. They have not been able to test GT500 heads yet, but they are certain that they will fit as well.

Both wet-sump and dry-sump oiling systems can be utilized.

Mihovetz says that perfection was the goal—”That’s the purpose of this product, we want to make sure that we’ve done all the engineering on our part so that the customer doesn’t have to. Most of the customers who buy this stuff are not necessarily as equipped as we are, I don’t want someone to spend this much money and come back and say ‘we spent 3 more days tapping stuff or boring holes.’ We want this thing to come out of the box, they can hone the cylinders for the size and finish that they want, and then put it together. It’s completely machined and deburred everywhere—there isn’t one bur on that block to touched. There’s nothing to be modified.”

Accufab eliminated the side mounting provisions because race motors are mounted with motor plates. This was also to prevent people from using solid motor mounts that could put the engine in a bind. 

The block weighs 112 pounds versus the 95 pounds of the factory variant, and it will easily handle over 3,500 horsepower, cites Mihovetz. 

The price is $13,500 and is sold exclusively through Accufab Racing. 

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