Stripped Chevy Starter Bolt Threads?

A recent customer reached out after installing a rebuilt engine from Jasper Engines in a Chevy. The issue? Stripped threads in the block for the starter bolts—specifically the 3/8-16 size. It's a frustrating spot to find yourself in, especially on a fresh rebuild, where the threads start about 1/2" down into a blind hole with roughly 15/16" of usable thread depth. The starter needs solid hold to avoid any movement or chomping on the flywheel during cranking.

Hello, I'm Dennis Bandy, owner of Wise Auto Tools and a Master Automotive Technician with decades in the shop. The tech who contacted me was clearly stressed and worried—he was staring down the very real possibility of having to pull the engine and swap it for another one, something he really did not want to do. That kind of setback is a nightmare: more labor, more downtime, more expense, and a lot of explaining to the customer. Stripped starter bolt holes aren't uncommon on these engines—I've seen it pop up on various Chevy small blocks and big blocks over the years, often from over-torquing, cross-threading, or just age and vibration loosening things up.

When a customer buys a remanufactured engine expecting everything perfect, this kind of surprise can eat up time and add unnecessary frustration.To their credit, Jasper Engines referred the tech directly to us for a professional thread repair solution. We've helped them (and many of their customers) in the past with similar issues, so they knew Time-Sert could save the day without major disassembly.

The key challenges here are twofold: First, the threads are recessed—they start about 1/2" below the surface of the block. Second, the starter bolts themselves are not fully threaded; they have a smooth shank section before the threaded portion begins. This design is intentional on many Chevy applications to allow proper alignment and to prevent the bolt from bottoming out or binding before the head seats fully against the starter flange. Because of that unthreaded shank, you can't simply use a standard thread repair insert that brings threads all the way to the surface—the bolt would never engage properly if the repair extended too high.Standard inserts like our regular 3/8-16 Time-Sert options (e.g., 0381 or 038190) work great for surface-level threads, but they don't address recessed starting points or account for the partial threading on the bolt itself. After reviewing the details with the tech and consulting Time-Sert directly, the right solution is their dedicated 3/8-16 Starter Bolt Thread Repair Kit (PN 1535). This kit is built specifically for these exact scenarios:

It includes all the tools needed: drill, counterbore, tap, installation driver, reamer, and four special inserts (P/N 153501).
The inserts feature a built-in straight (unthreaded) section at the top for proper bolt alignment—critical so the starter bolt's smooth shank can pass through cleanly and the threaded portion engages exactly where it should.
The hole needs a minimum depth of 1.200" (about 30mm) for the repair to work properly, which matched the customer's measurements closely enough after prep.
It's designed for first-time repairs on stripped 3/8-16 starter threads in cast iron or aluminum blocks, and it can even fix failed coil-style inserts if that's what was there previously.
The inserts are solid steel (not flimsy coils), providing a permanent, stronger-than-original fix.

This kit ensured the starter mounted securely without any play, and the built-in recess/alignment feature perfectly handled both the recessed thread start and the non-fully-threaded nature of the starter bolts—no need for workarounds that might compromise the job. Best of all, the repair was done in place, saving the tech from pulling the engine.

As an authorized distributor of Time-Sert products since we opened in 2005, we keep these kits in stock along with the full range of thread repair solutions. If you're dealing with a similar starter bolt issue—whether on a fresh Jasper rebuild, an older Chevy, or another application—don't mess around with temporary fixes or assume you have to yank the engine. Grab the PN 1535 kit or give us a call for guidance on sizing and installation. These repairs are straightforward with the right tools, but getting it right the first time saves headaches (and major labor) later. If this sounds like your situation, reach out via our contact page or check the product page here: Time-Sert 3/8-16 Starter Bolt Thread Repair Kit PN 1535. Safe wrenching and thanks for reading!

Dennis Bandy
Wise Auto Tools

19th Feb 2026 DennisB