With all the excitement surrounding the Shelby GT350 and its exotic, flat-plane crank-equipped 5.2-liter engine, you might wonder what that little extra displacement might be worth. There is, of course, more too it than just some extra cubes, as the bigger cylinders unshroud the Voodoo engine’s larger valves for enhanced flow, but what might .2 liter be worth on a Mustang GT?
Well, thanks to the crew at Coastal Chassis Dyno, we now know how much a few more cubes will do for a Whipple-supercharged S550. You see, Sam Lippencott and his team at CCD have become experts at upgraded Mustang GTs with cross-plane 5.2-liter engines of all sorts and one such car only received a displacement bump.
Nick Basilis brought his brought his Coyote-powered machine to Coastal Chassis Dyno to replace a wounded short-block. Sam Lippencott and the CCD team upgraded it with a new 5.2-liter short-block.
“A lot of people have been trying to do what we are doing with these blocks and have had massive failures, 100 percent has been user error,” Sam explained. “There are several things that have to be done different on these things to make them work correctly. The block failures have mostly been from people trying to use Coyote head studs in them and cracking the water jacket etc. It’s an expensive lesson to learn so people try to blame the block, I’ve yet to have a single issue.”
There is really no incurred expense that’s any different from a standard Coyote build. —Sam Lippencott, Coastal Chassis Dyno
For most of his cross-plane 5.2-liter engine builds, Sam employs a Ford crankshaft with Manley rods. Depending on the application he opts for JE or Diamond pistons, and Total Seal rings.
“There is really no incurred expense that’s any different from a standard Coyote build, except for the block itself. You can realistically just buy your standard, big-bore Coyote piston. That’s all you need to do. It’s not like it has to be a ‘5.2’ piston,” Sam said. “Ring-wise, you are basically using the same type of rings as what we use in the GT500s. It’s just because of the cylinder coating. The super-exotic, unicorn tears and pixie-dust coating that’s in there.”
Pullied for about 9 pounds of boost, Nick’s Whipple-boosted S550 picked up nice gains throughout the powerband with the addition of a 5.2-liter short-block filled with robust reciprocating parts.
Yes, that plasma transfer wire arc process used for the Voodoo block’s cylinder liners is pretty exotic, but the build for this particular car was as simple as short-block swap.
“You have to understand, too, that 90 percent of the time you are not doing this. If you are building a new motor, you are going to turn everything up. This is one of the few where we just said, ‘Let’s see what it does,’ to see if it made any difference at all,” he said. “Most of the time, as soon as you build the motor, you go all out. The problem with this one was that somebody else had built the motor that was in the car before and it had issues. So, we ended up taking that motor out and building the 5.2.”
Coastal uses the production 5.2-liter block, which is available from Ford Performance. This is the same aluminum block used in the Shelby GT350.
We basically just swapped everything over to the new motor with the 5.2. — Sam Lippencott, Coast Chassis Dyno
Putting the combo back together with no changes other than the short-block afforded us the opportunity to see what .2 liters of displacement is worth. It’s not a ton, but as you can see on the dyno graph it pulls harder throughout the rpm range.
“This is just a 5.2 and everything else is the same as it was before with the 5.0-liter motor—same compression ratio. We didn’t change anything. It was a 2.9 Whipple that was only making like 9 pounds (of boost),” Sam said. “We basically just swapped everything over to the new motor with the 5.2. The car did drop a little boost because of the added displacement, but the car picked up 10, 15, 20 (horsepower), pretty much across the board.”
To round out the engine, Coastal fills the 5.2-liter block with forged pistons (from Diamond or JE), Total Seal Rings, and Manley connecting rods.
Could this combo hold even more power? Sure, but for your average under-four-digit street machine, a fortified 5.2 should fit the bill.
“We haven’t tried to make 1,500 horsepower with one, but for 900 to 1,000 horsepower, it (the durability) hasn’t been an issue,” Sam added.
How much is .2 liters of displacement worth on a Whipple-blown Mustang? At the peaks Nick’s ride picked up 17 horsepower and 8 lb-ft of torque, but you can see it pulls stronger throughout the RPM range. The average power was up by 24 horsepower and 26 lb-ft of torque.