


The Ford 7.3L Powerstroke is renowned for its "indestructible" bottom end, but as enthusiasts push these engines to higher horsepower and torque levels, the factory main bolts become a point of concern. The ARP 250-5401 Main Stud Kit provides the essential foundation for any high-performance 7.3L build, offering the clamping force needed to prevent "main cap walk" and ensure long-term rotating assembly reliability.
By upgrading to 8740 Chrome Moly studs, you are protecting your crankshaft and main bearings from the stresses of high-boost tuning and heavy-duty competition.
High-Strength 8740 Material: Heat-treated in-house to a tensile strength of 200,000 psi, providing a massive upgrade in strength and fatigue life over the factory main bolts.
Eliminate Main Cap Walk: High torque and high-RPM harmonics can cause the main caps to shift or vibrate against the block. These studs provide the extreme vertical pressure required to lock the caps in place, preventing fretting and bearing damage.
Superior Torque Accuracy: Because the stud remains stationary and only the nut rotates, you eliminate the "twisting" (torsional) stress common with bolts. This results in a more consistent and accurate clamping force across all main journals.
Cold-Forged Integrity: Threads are rolled after heat treatment, ensuring the fasteners have maximum fatigue life—essential for the heavy reciprocating mass of a 7.3L diesel.
Protects Your Block: Studs are much easier on the block's internal threads than bolts. Since the stud stays in the block during the torque process, it reduces the risk of thread galling or stripping in the engine webbing.
While the 7.3L bottom end is naturally robust, it was not designed for the 500+ HP and 1,000+ lb-ft of torque that many modern builds achieve. When you increase the load on the crankshaft, the main caps are the only thing keeping it in place. If those caps move even a fraction of a millimeter, it can compromise the oil film and lead to a catastrophic spun bearing.
The ARP 250-5401 kit is the "gold standard" for bottom-end reinforcement. Whether you are building a reliable million-mile tow rig or a dedicated sled-pulling engine, these studs provide the structural integrity required to keep your rotating assembly spinning true.
Professional Machinist Note: Because ARP studs provide a significantly higher clamping force than factory bolts, it is highly recommended to have your block line-honed with the new studs installed. This ensures the main bores remain perfectly round under the new, higher tension.
PLEASE READ AND FILL OUT THE WARRANTY REGISTRATION FORM TO ACTIVATE THE WARRANTY.

Supplied with every engine is a complete copy of our warranty with an attached warranty registration form. This form can also be found here. Once filled out:
Then email a copy of each document within 45 days from the time of purchase to warranty@choateperformance.com. You should also retain a copy for your records as it may be required to assist with a warranty concern.
MODEL C STANDARD WARRANTY
1 Year / Unlimited Miles

THIS WARRANTY IS WITH THE PURCHASE OF THE INSTALLATION PACKAGE AND IS FOR THE ENGINE/WORKMANSHIP ONLY. NO LABOR PAYOUTS.
EXTENDED COMMERCIAL WARRANTIES ARE NOT AVAILABLE ON WORKHORSE, CASSQUATCH RACE SERIES, OR MODEL C ENGINES.
Remanufactured Heads — 6 Months
PARTS ONLY

Cylinder heads are warranted to be free from defects in material and workmanship. This warranty does not cover cylinder heads that are damaged due to improper installation, overheating, abuse, or accident.
Short Block Engines

Warranty coverage for Short Block engines does not include labor payout. We do not cover fluid leaks on any Short Block builds.
DAILY DRIVER WARRANTY
5 Year / 100,000 Miles

THIS WARRANTY IS NOT A FULL COVERAGE WARRANTY. PLEASE REVIEW YOUR WARRANTY CAREFULLY.
Labor rate for PREFERRED DEALER ONLY is a higher shop rate using Mitchell flat rate time.
WORKHORSE SERIES ENGINE
5 Year / 100,000 Miles

THIS WARRANTY IS NOT A FULL COVERAGE WARRANTY. PLEASE REVIEW YOUR WARRANTY CAREFULLY.
Labor rate for PREFERRED DEALER ONLY is a higher shop rate using Mitchell flat rate time.
YOUR CASSQUATCH RACE ENGINE
6 Months / 3,000 Miles
PARTS ONLY

THIS WARRANTY IS NOT A FULL COVERAGE WARRANTY. PLEASE REVIEW YOUR WARRANTY CAREFULLY.
CHOATE ENGINEERING PERFORMANCE COMMERCIAL WARRANTY
1 Year / 20,000 Miles

THIS WARRANTY IS NOT A FULL COVERAGE WARRANTY. PLEASE REVIEW YOUR WARRANTY CAREFULLY.
Labor rate for PREFERRED DEALER ONLY is a higher shop rate using Mitchell flat rate time.
CHOATE ENGINEERING PERFORMANCE EXTENDED COMMERCIAL WARRANTY
3 Year / 60,000 Miles

THIS WARRANTY IS NOT A FULL COVERAGE WARRANTY. PLEASE REVIEW YOUR WARRANTY CAREFULLY.
WARRANTY COVERAGE DETAILS
This warranty will cover remanufactured Short and Long-Block engines that are built by Choate Engineering Performance unless otherwise stated. From this page on, engines will be referred to as “unit(s)” and/or “engine(s)” unless otherwise stated. Fuel pump, injectors, and turbo warranties, and warranties on all accessories, are covered by the supplying manufacturer’s warranty.
FOR PREFERRED DEALERS ONLY: LABOR RATE IS SET AT A HIGHER RATE PER HOUR UP TO A MAXIMUM OF $2,500, NO EXCEPTIONS.
THE LIMITED WARRANTY WILL BE VOID AND WILL NOT APPLY TO DEFECTS OR FAILURES CAUSED BY THE FOLLOWING:
BUYER ALSO ACKNOWLEDGES THAT PROPER MAINTENANCE PROCEDURES ARE REQUIRED TO KEEP THE UNIT IN PROPER WORKING ORDER. CHOATE ENGINEERING PERFORMANCE WILL NOT ASSUME ANY RESPONSIBILITY FOR THE COST OF THIS ROUTINE MAINTENANCE.
Buyer acknowledges the following:
This warranty will not cover damages caused by the following for remanufactured engines:
Choate Engineering Performance limited warranty will end after the expiration of time or mileage from the date of the original invoice. Any repairs or replacements will not extend the warranty. The buyer shall be responsible for all defects thereafter, regardless of cause. Choate Engineering Performance limited warranty is in lieu of all other warranties expressed or implied.
The buyer agrees Choate Engineering Performance will not be responsible for:
TO QUALIFY FOR THE 5 YEAR / 100,000 MILE WARRANTY YOU MUST FOLLOW ALL INSTRUCTIONS AND REPLACE ALL PARTS SPECIFIED.
THIS WARRANTY IS TRANSFERABLE THROUGH PRIVATE SALE AND CHANGE OF OWNERSHIP ONLY ONCE IF CERTAIN CRITERIA ARE MET.
CHOATE ENGINEERING PERFORMANCE LIMITED WARRANTY FOR THE WORKHORSE AND CASSQUATCH SERIES ENGINES IS IN ADDITION TO ALL ITEMS LISTED IN THE STANDARD WARRANTY PACKAGE AND SUPERSEDES ALL MILEAGE REQUIREMENTS.
The Limited Warranty specifically does not cover the following:
FREIGHT / SHIPPING CHARGES

CHOATE ENGINEERING PERFORMANCE SHALL NOT BE RESPONSIBLE, NOR SHALL IT PAY ANY FREIGHT/SHIPPING CHARGES.
ADDITIONAL INFORMATION

As consideration for the above warranties, the buyer agrees they will take no action, statement, characterization, or implication regarding Choate Engineering Performance that may in any manner be interpreted as disparaging to Choate Engineering Performance or the reputation of Choate Engineering Performance. Any violation of this is a material breach, entitling Choate Engineering Performance to void any warranty.