Denso 4PR-U Resistor U-Groove Spark Plug

DENSO's patented U-Groove spark plug enables complete combustion by allowing the spark to fill the gap created by the U shape. The ball of fire created in the U-Groove develops a larger and hotter flash front that virtually eliminates excessive fouling and erratic starts caused by poor fuel mixtures.

Even DENSO's "standard" spark plug is something special. The innovative design that helped to make DENSO spark plugs famous, the U-groove plug employs a unique, channeled ground electrode designed to generate a larger spark nucleus at the point of ignition. Greater spark energy than ordinary plugs means improved flame travel, producing more complete, consistent, and efficient combustion.

Vehicle Fitments:

Year	Make	Model	Submodel
1954 - 1958	Buick	Century	Base
1959 - 1961	Buick	Electra	225, Base
1967	Buick	Gran Sport	Base
1959 - 1961	Buick	Invicta	Base
1959 - 1966	Buick	LeSabre	Base
1965 - 1966	Buick	LeSabre	Custom
1958	Buick	Limited	Base
1957	Buick	Roadmaster	75
1951 - 1958	Buick	Roadmaster	Base
1954 - 1967	Buick	Skylark	Base
1951 - 1967	Buick	Special	Base
1961 - 1967	Buick	Special	Deluxe
1965	Buick	Sportwagon	Base
1951 - 1958	Buick	Super	Base
1965 - 1967	Cadillac	Calais	Base
1955 - 1967	Cadillac	DeVille	Base
1955 - 1967	Cadillac	Eldorado	Base
1963 - 1964	Cadillac	Eldorado	Biarritz
1957 - 1960	Cadillac	Eldorado	Brougham
1965 - 1967	Cadillac	Fleetwood	75, 60 Special
1966 - 1967	Cadillac	Fleetwood	Base
1955 - 1964	Cadillac	Series 60 Fleetwood	Base
1955 - 1964	Cadillac	Series 62	Base
1958	Cadillac	Series 70 Fleetwood Eldorado	Base
1955 - 1964	Cadillac	Series 75 Fleetwood	Base
1962 - 1968	Chevrolet	Bel Air	Base
1965 - 1968	Chevrolet	Biscayne	Base
1969 - 1970	Chevrolet	Blazer	Base
1970	Chevrolet	C10 Pickup	Base
1970	Chevrolet	C10 Suburban	Base
1970	Chevrolet	C20 Pickup	Base
1970	Chevrolet	C20 Suburban	Base
1970	Chevrolet	C30 Pickup	Base
1967 - 1970	Chevrolet	Camaro	Z28, Base, SS, RS
1967 - 1968	Chevrolet	Caprice	Base
1967 - 1968	Chevrolet	Chevelle	300
1967 - 1969	Chevrolet	Chevelle	300 Deluxe
1964 - 1970	Chevrolet	Chevelle	Base, SS
1967 - 1970	Chevrolet	Chevelle	Concours
1965 - 1967	Chevrolet	Chevelle	Deluxe
1969 - 1970	Chevrolet	Chevelle	Greenbrier, Concours Estate
1968 - 1970	Chevrolet	Chevelle	Malibu, Nomad
1967 - 1968	Chevrolet	Chevy II	Nova
1967	Chevrolet	Chevy II	Nova SS, Base
1962 - 1968	Chevrolet	Corvette	Base
1968	Chevrolet	El Camino	SS, Custom, Base
1970	Chevrolet	G10 Van	Sportvan, Base
1965 - 1968	Chevrolet	Impala	Base
1965 - 1967	Chevrolet	Impala	SS
1970	Chevrolet	K10 Suburban	Base
1970	Chevrolet	K20 Suburban	Base
1970	Chevrolet	K30 Pickup	Base
1964 - 1967	Chevrolet	Malibu	Base
1969 - 1970	Chevrolet	Nova	Base
1957 - 1967	Chrysler	300	Base
1962 - 1963	Chrysler	300	Sport
1975 - 1978	Chrysler	Cordoba	Base
1957 - 1958	Chrysler	Imperial	Base, Crown
1958	Chrysler	Imperial	LeBaron
1957 - 1958	Chrysler	New Yorker	Base
1975 - 1978	Chrysler	New Yorker	Brougham
1957 - 1978	Chrysler	Newport	Base
1972 - 1976	Chrysler	Newport	Custom
1972	Chrysler	Newport	Royal
1957 - 1977	Chrysler	Town & Country	Base
1975 - 1976	Dodge	Coronet	Brougham, Base, Crestwood
1975	Dodge	Coronet	Custom
1978	Dodge	Magnum	XE
1975 - 1978	Dodge	Monaco	Base
1977 - 1978	Dodge	Monaco	Brougham, Crestwood
1975 - 1976	Dodge	Monaco	Royal, Royal Brougham
1977	Dodge	Royal Monaco	Brougham, Base
1968 - 1971	Oldsmobile	442	Base
1965 - 1972	Oldsmobile	98	Base
1965 - 1967	Oldsmobile	98	Holiday
1971 - 1972	Oldsmobile	Custom Cruiser	Base
1964 - 1971	Oldsmobile	Cutlass	Base
1964 - 1967	Oldsmobile	Cutlass	Holiday
1971	Oldsmobile	Cutlass	S
1967	Oldsmobile	Cutlass	Turnpike Cruiser
1971	Oldsmobile	Cutlass Supreme	Base
1967 - 1968	Oldsmobile	Delmont 88	Base
1967	Oldsmobile	Delmont 88	Holiday
1965 - 1972	Oldsmobile	Delta 88	Base
1967 - 1971	Oldsmobile	Delta 88	Custom
1965 - 1967	Oldsmobile	Delta 88	Holiday
1969 - 1972	Oldsmobile	Delta 88	Royale
1965 - 1966	Oldsmobile	Dynamic 88	Holiday, Base
1964 - 1970	Oldsmobile	F85	Base
1964 - 1966	Oldsmobile	F85	Deluxe
1966	Oldsmobile	F85	Holiday
1964 - 1966	Oldsmobile	Jetstar 88	Holiday, Base
1965 - 1966	Oldsmobile	Starfire	Base
1966 - 1971	Oldsmobile	Toronado	Base
1971	Oldsmobile	Toronado	Brougham
1968	Oldsmobile	Toronado	Custom
1966 - 1967	Oldsmobile	Toronado	Deluxe
1964 - 1970	Oldsmobile	Vista Cruiser	Base
1964 - 1967	Oldsmobile	Vista Cruiser	Custom
1974 - 1978	Plymouth	Fury	Base
1975	Plymouth	Fury	Custom
1972 - 1975	Plymouth	Fury	Custom Suburban
1972	Plymouth	Fury	Gran Coupe, Gran Sedan
1974	Plymouth	Fury	Police
1976 - 1978	Plymouth	Fury	Salon
1975 - 1978	Plymouth	Fury	Sport
1972 - 1978	Plymouth	Fury	Suburban, Sport Suburban
1972 - 1974	Plymouth	Fury I	Suburban, Base
1972 - 1974	Plymouth	Fury II	Custom Suburban, Base
1972 - 1974	Plymouth	Fury III	Sport Suburban, Base
1975 - 1977	Plymouth	Gran Fury	Brougham, Sport
1975 - 1976	Plymouth	Gran Fury	Custom
1972 - 1976	Plymouth	Gran Fury	Custom Suburban
1972 - 1977	Plymouth	Gran Fury	Suburban, Sport Suburban, Base
1976 - 1978	Plymouth	PB200	Voyager
1976 - 1978	Plymouth	PB300	Voyager
1973 - 1975	Plymouth	Road Runner	Base
1972 - 1974	Plymouth	Satellite	Sebring, Custom, Sebring Plus, Regent, Base
1977 - 1978	Plymouth	Trailduster	Base
1960 - 1962	Pontiac	Bonneville	Custom
1960 - 1970	Pontiac	Bonneville	Safari, Base
1964 - 1967	Pontiac	Catalina	2+2
1960 - 1969	Pontiac	Catalina	Safari, Base
1962 - 1969	Pontiac	Catalina	Ventura
1967 - 1970	Pontiac	Executive	Base, Safari
1967	Pontiac	Firebird	326
1968 - 1969	Pontiac	Firebird	350
1969	Pontiac	Firebird	350 HO
1967 - 1969	Pontiac	Firebird	400, Sprint
1967 - 1970	Pontiac	Firebird	Base
1970	Pontiac	Firebird	Formula, Esprit
1967 - 1968	Pontiac	Firebird	HO
1969 - 1970	Pontiac	Firebird	Trans Am
1962 - 1970	Pontiac	Grand Prix	Base
1964 - 1970	Pontiac	GTO	Base
1970	Pontiac	GTO	The Judge
1963 - 1970	Pontiac	LeMans	Base
1969 - 1970	Pontiac	LeMans	Safari
1970	Pontiac	LeMans	Sport
1960 - 1966	Pontiac	Star Chief	Base
1966	Pontiac	Star Chief	Executive
1961 - 1970	Pontiac	Tempest	Base
1961 - 1969	Pontiac	Tempest	Custom, Safari
1970	Pontiac	Tempest	GT
1961	Pontiac	Tempest	LeMans
1960 - 1961	Pontiac	Ventura	Base