I heard the sickening bang of a connecting rod exiting the side of the engine block on a 1967 Corvette 427/435hp. The car is “Numbers Matching,” meaning the VIN on the engine matches the car. This pedigree adds $50,000 to the car’s value. The insurance adjuster offered to pay $8,000 for a brand new “Crate Engine.” I screamed NO. Putting a new engine in would destroy the investment value of the car.
Key Takeaways
- The Value is in the Stamp: For investment cars, the original block is irreplaceable. A crate motor makes it a “driver,” not a “survivor.”
- Welding is Expensive: Repairing a cast iron block requires a specialized oven, TIG welding, and re-machining. It costs 3x more than a new engine.
- Diminished Value (DV): Even if repaired, a welded block is worth less. You need a policy that covers DV.
- Mechanical Breakdown Exclusion: This is the biggest hurdle. If the rod threw because of “wear and tear,” it’s denied. You must prove it was a “covered peril” (e.g., impact to oil pan, bad fuel, or fire).
The “Why” (The Trap): Functional Replacement
The policy pays to “repair or replace with like kind and quality.”
Functionally, a new GM Crate Engine is better than the old one. It has a warranty and more power.
The insurer argues they are upgrading you.
You argue they are destroying the provenance. Most policies do not recognize provenance unless explicitly stated.
[IMAGE: Photo of an engine pad stamp with VIN numbers vs. a generic replacement block]
The Investigation: I Called Them
I assumed the engine failure was caused by a covered peril (e.g., oil pan hit a rock). How do they fix it?
1. Porsche Auto Insurance (Agreed Value)
- Stance: They understand “Matching Numbers.”
- Offer: They authorized shipping the case to a specialist in Germany for laser welding. Cost: $25,000.
- Verdict: The best for European marques.
2. State Farm Classic
- Stance: “We replace the motor.”
- Offer: $6,000 for a crate motor and labor.
- Verdict: Disaster for a collector.
3. Hagerty
- Stance: They support “Preservation.”
- Offer: They paid for the complex repair to save the block.
- Verdict: They get it.
Comparison Table
| Repair Method | Cost | Value of Car After Repair | Insurance Preference |
| New Crate Motor | $6,000 | -$40,000 (Loss of Pedigree) | Standard Carrier |
| Weld Original Block | $15,000 | -$5,000 (Welded but matching) | Specialty Carrier |
| Used Date-Coded Block | $10,000 | -$10,000 (Correct era, wrong VIN) | Middle Ground |
Step-by-Step Action Plan
- Establish Cause: You must prove the failure wasn’t just old age. Did you hit debris? Did the oil cooler line get cut? Find an accidental cause.
- Get a Diminished Value Appraisal: Before accepting a crate motor, get a report saying: “Installing a non-original engine reduces market value by $50,000.”
- Find a Specialist: Do not let a general mechanic fix a numbers-matching block. Send it to a specialist (e.g., specific Corvette or Ferrari machine shop).
- Keep the Old Block: If they force a replacement, keep the broken block. It belongs to the car. Future buyers will want it even if it’s broken.
FAQ Section
Is a thrown rod covered?
Usually NO. That is “Mechanical Breakdown.” Unless you can prove an external cause (oil pan impact), internal failure is maintenance, not insurance.
What if the shop ruins the engine?
That is “Garagekeepers Liability.” The shop’s insurance pays.
Does “Numbers Matching” really matter for insurance?
Yes, it justifies the high “Agreed Value.” If you swap the engine, you must lower your Agreed Value or disclose the modification.