Diamond Forged Pistons - GM LS7 - 4.000 in Stroke, 6.077 in Rod
Diamond Forged Pistons - GM LS7 - 4.000 in Stroke, 6.077 in Rod
Diamond forged pistons for GM LS7
Eight-piston engine-build kits for the specified crankshaft, connecting rods and finished cylinder bore. Select the bore, crown and nominal compression ratio, then choose the standard or upgraded H13 gudgeon-pin kit.
Representative Diamond catalogue photograph. Crown shape, valve reliefs, skirt finish and supplied components may differ by the selected part number.
Made to order and delivery
Special-order, made-to-order pistons. Allow approximately 5–6 weeks for delivery, pending Australian customs processing time. Manufacturing schedules, international freight and clearance can extend this estimate.
Features and included components
- Forged 2618 aluminium construction, machined in the USA.
- Machined crown and valve-relief profiles; verify the chosen cylinder head and camshaft combination.
- Offset pins and moly-coated skirts.
- Trend gudgeon pins, the listed ring set and pin retainers included.
- Standard-pin and upgraded H13 kits available as separately priced options.
- Catalogue compression figures use a 0.040-inch head gasket; actual ratio depends on the measured engine assembly.
Build dimensions
- Crankshaft stroke: 4.000 inch
- Connecting-rod length: 6.077 inch
- Compression height: 1.163 inch
- Gudgeon-pin diameter: 0.9252 inch
- Quantity: eight pistons; rings, pins and retainers included. Oil-rail supports are included where indicated in the kit table.
Kit selection
| Kit SKU | Bore | Crown volume | Nominal ratio | Included pin | Ring set | Ring thickness | Retainer | Oil-rail supports |
|---|---|---|---|---|---|---|---|---|
| 11581-R1-8 | 4.130 IN | -3.84 CC | 11.50:1 | G9252250185C | 09454130 | 1.20 MM x 1.20 MM x 3.00 MM | 015111-16 | Yes |
| 11591-R1-8 | 4.130 IN | -23.00 CC | 9.50:1 | G9252250185C | 09454130 | 1.20 MM x 1.20 MM x 3.00 MM | 015111-16 | Yes |
| 11581-R1-8-H | 4.130 IN | -3.84 CC | 11.50:1 | H9272250225C | 09454130 | 1.20 MM x 1.20 MM x 3.00 MM | 015111-16 | Yes |
| 11591-R1-8-H | 4.130 IN | -23.00 CC | 9.50:1 | H9252250225C | 09454130 | 1.20 MM x 1.20 MM x 3.00 MM | 015111-16 | Yes |
Fitment and installation
For LS7 cylinder-head and block combinations using a 4.000-inch stroke and 6.077-inch rods. Confirm sleeve condition, finished bore and valve clearance. This listing is specific to the stated rod length and must not be interchanged with the other LS7 rod-length group.
The gudgeon-pin diameter for this group is 0.9252 inch. Rod small-end diameter, rod length and pin retention must match the selected kit. The standard and H13 options are priced as complete eight-piston kits.
Have your engine builder check piston-to-bore clearance, ring gaps, deck height, piston-to-valve clearance and rotating-assembly balance before assembly. Nominal compression ratios are selection guides, not a substitute for measuring the chamber, gasket and deck volumes.
BBT workshop support and related parts
Boost & Tune can help coordinate the piston, rod and crank dimensions with your planned naturally aspirated or boosted LS build. Contact BBT with your engine code, measured bore, cylinder heads and target use before ordering if the combination is not already specified.