ARP 145-4012 Head Stud Kit for Mopar Koffel BTS

It is for good reason that virtually every top professional engine builder relies on ARP Pro Series head studs for their all-out competition powerplants. Simply stated, there’s not a better stud setup on the market today.

For openers, ARP uses a premium grade 8740 alloy that is rated far superior to “aircraft” quality. Each stud is placed vertically in special racks and precisely heat-treated to 200, 000 psi. This procedure ensures complete heat penetration and the results are far superior to those lesser quality studs from other manufacturers who just dump pieces in a basket and hope for the best.

Following heat-treat, each stud is centerless ground to make it as close to perfectly concentric as possible. This procedure involves about ten very slight cuts and results in an exceptionally straight part. It’s important to note that lesser quality studs are not even centerless ground – the material is thread rolled in bar stock form (mostly before heat-treat, when the material is easier to machine). Because ARP studs are manufactured to such exacting tolerances, you will note that gaskets and cylinder heads literally glide into position and are perfectly aligned – something that won’t happen with inferior quality head studs.

ARP studs are thread rolled after heat-treat, which gives them about 1000% (that’s ten times) better fatigue strength than those studs that are threaded prior to heat-treat (a very common industry practice). It costs a lot more to do it this way, because it’s tough on tooling, but the results are well worth the extra effort.

You will also note that ARP offers specially undercut studs for several engines. This procedure (done only to the shorter studs) more equalizes the “stretch” of both studs, which makes for a more consistent clamping force – and one that compensates for head gasket compression when the cylinder heads are installed. This helps prevent blown head gaskets, and assures optimum engine sealing!

Premium quality heat-treated 8740 chrome moly steel head stud kits are available for most every domestic and import applications.

You won’t find a better quality stud on the market from any other source. Look for ARP stamped on each stud as your assurance of quality.

Clearly, ARP Head Stud/Bolt Kits are the best on the market today, and the favorite of leading professional engine builders in all forms of racing.

HIGH PERFORMANCE SERIES: High Performance head bolts are available with a reduced wrenching hex or 12-point and wide area flanged head that eliminates the need for valve train removal to facilitate cylinder head retorquing. All High Performance Series bolts are 180, 000 psi (which is 15% stronger than Grade 8) and kits come complete with hardened parallel-ground washers.

PRO SERIES: All Pro Series bolts are cold-forged to ensure molecular integrity, heat-treated prior to thread rolling and machining, and are rated nominally at 200, 000 psi. ARP Pro Series head bolt kits are application specific – designed for use with typically competition only components. These fasteners deliver superior strength and meet the ARP “ZERO defect – ZERO failure” quality standard. Hardened and parallel-ground washers are included with each kit to ensure even load distribution and accurate torque readings. All Pro Series head bolts have a reduced wrenching hex or 12-point head and wide area flange to eliminate the need for valve train removal for cylinder head retorquing and permits the use of larger diameter valve springs. Most applications have undercut short bolts that can help eliminate head gasket failures through providing more “stretch” to compensate for the additional compression of gaskets.

Head Studs vs Bolts: On many street-driven vehicles, where master cylinders and other items protrude into the engine compartment, it’s probably necessary to use head bolts so that the cylinder heads can be removed with the engine in the car.

For most applications, however, studs are recommended. And for good reason. Using studs will make it much easier to assemble an engine (especially a racing powerplant which must be serviced frequently and quickly!) with the cylinder head and gasket assured of proper alignment.

Studs also provide more accurate and consistent torque loading. Here’s why. When you use bolts to secure the head, the fastener is actually being “twisted” while it’s being torqued to the proper reading. Accordingly, the bolt is reacting to two different forces simultaneously. A stud should be installed in a “relaxed” mode – never crank it in tightly using a jammed nut.

If everything is right, the stud should be installed finger tight. Then, when applying torque to the nut, the stud will stretch only on the vertical axis. Remember, an undercut shorter stud will have a rate similar to a longer, standard shank stud. This provides a more even clamping force on the head. Because the head gasket will compress upon initial torquing, make sure studs and bolts are re-torqued after the engine has been run.

Finish: Black oxide
Material: 8740 Chrome Moly
Quantity: Kit 

Kit Instructions

Supported Vehicles:

Chrysler
300 1959-1971
Cordoba 1975-1978
Imperial 1959-1975
New Yorker 1963, 1966-1978
Newport 1961-1978
Saratoga 1959-1960
Town and Country 1959-1977
Windsor 1959-1961

Dodge
330 1963-1964
440 1963-1964
880 1963-1964
B-Series 1971-1978
CB300 1976-1979
Challenger 1970-1974
Charger 1966-1978
Coronet 1958-1959, 1965-1976
Custom 1958-1959
Dart 1960-1962, 1967-1969
DW Pickup 1967-1978
Lancer 1958-1959
Magnum 1978
Matador 1960
MB300 1974
Monaco 1965-1978
Phoenix 1960-1961
Pioneer 1961
Polara 1960-1973
Power Wagon 1967-1974
Ramcharger 1974-1978
Royal 1958-1959
Seneca 1961
Sierra 1958-1959
Suburban 1958
Truck 1960

Plymouth
Barracuda 1964, 1967-1972
Belvedere 1958, 1960-1970
Fleet Special 1960-1963
Fury 1958, 1960-1978
GTX 1967-1971
PB-Series 1974, 1976-1978
Plaza 1958
Satellite 1965-1974
Savoy 1958, 1960-1964
Sport Suburban Wagon 1960-1961
Suburban 1958, 1960-1961
Superbird 1970
Trailduster 1974-1978
VIP 1967