list of terms only Mopar people know
Another term not unique to Chrysler Corp.
The Chevy Big blocks were true Semi-Hemis, as were the Ford Boss 429's, and both were called by that designation.
In 1965, Chevrolet formally announced a new big block V8. Available first as a 396 cubic inch version, the engine eventually evolved to displacements of 402, 427 and 454 CI. Eventually, enthusiasts could buy a 572 cubic inch crate motor based on the same engine block.
Even after the engine was introduced, many people still continued to refer to it as the
Mystery Engine. When the valve covers were removed, hot rodders noticed that, unlike the mouse motor which had the valve stems neatly lined up in a row,
the valves in the new engine were canted at various angles. Because of this, the engine also gained the nick-name of the
Porcupine V8. When engine builders started modifying the engine for racing, they noted that
the cylinder heads had a somewhat hemispherical design. The engine wasnt a true hemi, but it wasnt exactly a wedge head, either. Thus the engine earned another name:
the Semi-Hemi.
Also, the Ford Boss 429 and the Ford 427 SOHC were also called a
"Semi Hemi" engines.
Ford had "Hemi" heads for the 429/460 block, also, that were used in NASCAR racing. The 429 version being available in the Boss 429 Mustang in 1969-70.
Additional versions of the Boss 429 engine were also made for the 1969 Can-Am racing championship. Using an aluminum block, in addition to a dry sump oil system and fuel injection, the engine was bored and stroked to 494 cubic inches,
