| I found this from a Muscle Mustang Article:
"Power for this Pro car starts with a Ford GT 5.4-liter supercar aluminum block that's been milled by VT Competition Engines (Lansing, Michigan) to accept a Darton Modular Integrated Deck. If you're not familiar with the Darton MID design, basically the cylinder walls of the block are milled out, leaving an open rectangular shape. The MID consists of interlocking metal cylinder sleeves that are precision fit into the block.
Once that was complete, the block was filled with Hardblock, a concrete type of mixture that solidifies once it is poured in. Duttweiler says this was done mainly to prevent blown head gaskets from spewing water out of the side of the heads, which could possibly get under the tires. It also makes the block a lot more stable and less prone to distortion. Once the Hardblock has filled the block, the water passages are then welded up in the heads, and the only thing that the head gaskets have to deal with is cylinder pressure, which is easily accomplished. Duttweiler says that the small bore size of the modular engine family helps them seal better. Flatout Gaskets of Mundelein, Illinois, supplied the copper gaskets and O-rings that seal the heads to the block.
Once the GT block was worked over, it was filled with a destroked Kellogg crankshaft with a 3.75-inch stroke, MGP aluminum connecting rods, and JE pistons that fit the 3.70-inch bores. Displacement is now 323 ci, and when combined with the CNC-ported GT500 cylinder heads, provides a stout 11:1 compression ratio, which is possible thanks to the location of the spark plugs in the combustion chamber, as well as the use of 118-octane race fuel."
Any more information than this if you need, I'd suggest contacting Kenny Duttweiller.  |