“Hemis Rule!” A blown Chrysler Hemi (or a Hemi clone) on fuel has been the ultimate power source for competitors racing in the top drag racing classes for the last forty years. If you wanted to find the most famous of these engines, it would arguably have to be the 392 cu. in. Hemi that went in the most famous and successful dragster of all time: The Greer, Black & Prudhomme AA/FD. And GMP has given us this engine in magnificent 1:6 scale!

Chrysler introduced the Hemi as the Chrysler Fire Power engine in the 1951 Chrysler 300C. This engine initially had 354 cu. in., but in 1957-58 was opened-up to 392 cu. in. The Fire Power engine was rated at 390 stock horsepower when fitted with the optional dual four-barrel carburetors. The term “Hemi” is short for Hemispherical used to describe the engine’s cylinder heads. By using a Hemispherical (literally half sphere) shaped combustion chamber, Chrysler was able to install bigger valves and have more charge surface area in this combustion chamber than they would have using the traditional “wedge head” design. This made for more horsepower and was particularly popular in Top Fuel Dragsters although they were also the favored engine for Gassers and Fuel Altereds.

The Greer, Black & Prudhomme engine had a GMC 6-71 blower topped with a four-port Hilborn injector, Schiefer roller cam, Schiefer “Frankenstein” magneto (although this one says Cirello as they took over manufacture and sales of the magneto from Schiefer) and a Schiefer “slipper” clutch. It also featured a unique Wayne Ewing-created injector scoop that took the place of the traditional Hilborn cast-aluminum scoop used earlier in the car’s life. In this configuration, run on a load of alcohol and nitromethane (50 to 100% nitro), with the blower overdriven to produce 15-18 PSI, this engine would deliver somewhere north of 1100 horsepower.

Once again, GMP has done a fabulous job of creating this engine for us. Since they have done two versions of the GB&P dragster and a 1:6 scale version of a Chrysler Hemi owned by GMP owner Tom Long, it was a natural that they would give us this iconic engine. But they’ve done it right changing all of the pieces that needed to be changed to make the engine correct. Gone is the Vertex mag replaced by the Schiefer/Cirello mag. The blower manifold has changed, as have the headers, and front timing chain cover. The engine comes semi-assembled (or semi-disassembled) and can be displayed at any step along the process of assembly as GMP has given us a convincing block with pistons, brass head gaskets, cylinder heads with realistic rocker arms, rocker arm shafts and valve springs and the chromed stock Chrysler valve covers. The engine even has a workable dipstick and dipstick tube, so if you need to check the oil, you can. The signature Ewing injector scoop can be set aside to reveal the working butterflies in the Hilborn four-holer. The scoop and valve covers are held in-place with tiny magnets that give a nice click when the pieces are assembled. The crankshaft can be turned by the crank flange on the back of the engine which in-turn rotates the blower belt and blower pulley. I have to say that it blows me away that neither of the 1:6 scale engine manufacturers……. GMP or Liberty…. seems concerned about including bell housings and flywheels. To me, the engine stops where the transmission or, in this case, the driveshaft starts. But I haven’t heard anyone else complain, so this must be my deal.

This engine mounts on an extremely heavy display stand with supports and a clear plastic cover to keep off dust and fingerprints. They even provide cotton gloves for the ultra-fastidious. The whole unit comes packaged in a foam cocoon inside a nicely-decorated box. This packaging insures that the engine will be well-protected and is an engineering marvel in itself.

In summary, GMP has done a glorious job of creating this beautiful engine that was the motive power for probably the most famous dragster ever! It’s convincingly real and stands as a reminder of Keith Black’s engine expertise and that this engine and the car it went in was a starting point for the drag racing careers of both Black and Prudhomme. Another beautiful job, GMP!

-Bill Bennett