Keith Black Hypereutectic Pistons, Pontiac 389, 3.750" Str., +.060", -3.5cc Flat Top, Set/8, UEM-KB370-060
Keith Black Hypereutectic Pistons — Set of 8
Pontiac 389
-3.5cc Flat Top
+.060"
3.750" Stroke
1.720" Compression Height
.980" x 3.000" Pins Included
5/64, 5/64, 3/16 Ring Pack (rings sold separately)
Description
Keith Black Pistons — Pontiac 389
+.060" · 3.750" Stroke · -3.5cc Flat Top · Set of 8
Keith Black hypereutectic pistons are the long-running standard for a stock-to-mild Pontiac rebuild. The high-silicon casting runs tighter piston-to-wall clearance than a forging, so it is quiet cold, seals well, and holds oil control for a long street life. It is not a power-adder piston — but for a numbers-matching rebuild or a mild cam and headers combination, it is the right part at the right money.
Specifications
| Part Number | UEM-KB370-060 |
|---|---|
| Brand | Keith Black |
| Material | Hypereutectic cast aluminum (390 alloy) |
| Application | Pontiac 389 |
| Oversize | +.060" |
| Stroke | 3.750" |
| Rod Length | 6.625" |
| Compression Height | 1.720" |
| OE Deck Height | 10.240" |
| Crown | Flat Top, -3.5cc |
| Pin Diameter | .980" |
| Pin Length | 3.000" |
| Pin Type | Press-fit or floating, centered |
| Lock Ring | PRH107-3 |
| Top Land | .200" |
| Intake Valve Relief (depth / dia.) | .237" / 2.100" |
| Exhaust Valve Relief (depth / dia.) | .237" / 2.100" |
| Compression Ratio (chamber cc - ratio) | 71cc-10.7, 87cc-9.2, 96cc-8.5, 111cc-7.6 |
| Ring Pack | 5/64, 5/64, 3/16 (sold separately) |
| Quantity | Set of 8 |
What You Get
- Eight Keith Black hypereutectic pistons
- .980" x 3.000" wrist pins and locks
Fitment & Installation Notes
- Will not work with 14-degree heads.
- For use with 20-degree heads, pre-1966.
- Piston sits .025" below the factory deck.
- Check rod small end to piston before assembly: .045" clearance per side minimum.
- Keith Black hypereutectic pistons require a much wider top ring end gap than traditional forged pistons. The KB spec is 0.0065" per inch of bore for a street engine.
Before you order: measure your finished bore before buying an oversize. Confirm chamber volume and deck height against your target compression ratio — crown volume alone does not set compression. Opened or installed pistons are not returnable.
Specifications/Information
| Part Number | UEM-KB370-060 |
|---|---|
| Brand | Keith Black |
| Material | Hypereutectic cast aluminum (390 alloy) |
| Application | Pontiac 389 |
| Oversize | +.060" |
| Stroke | 3.750" |
| Rod Length | 6.625" |
| Compression Height | 1.720" |
| OE Deck Height | 10.240" |
| Crown | Flat Top, -3.5cc |
| Pin Diameter | .980" |
| Pin Length | 3.000" |
| Pin Type | Press-fit or floating, centered |
| Lock Ring | PRH107-3 |
| Top Land | .200" |
| Intake Valve Relief (depth / dia.) | .237" / 2.100" |
| Exhaust Valve Relief (depth / dia.) | .237" / 2.100" |
| Compression Ratio (chamber cc - ratio) | 71cc-10.7, 87cc-9.2, 96cc-8.5, 111cc-7.6 |
| Ring Pack | 5/64, 5/64, 3/16 (sold separately) |
| Quantity | Set of 8 |
Notes
- Will not work with 14-degree heads.
- For use with 20-degree heads, pre-1966.
- Piston sits .025" below the factory deck.
- Check rod small end to piston before assembly: .045" clearance per side minimum.
- Keith Black hypereutectic pistons require a much wider top ring end gap than traditional forged pistons. The KB spec is 0.0065" per inch of bore for a street engine.
Details
- UEM-KB370-060
- UEM-KB370-060
- Keith Black
- New
Categories
Shipping Information
- Item Requires Shipping
- 16.0 lbs.
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