Diamond Forged Pistons - GM LS9 / LSA - 3.622 in Stroke, 6.125 in Rod
Diamond Forged Pistons - GM LS9 / LSA - 3.622 in Stroke, 6.125 in Rod
DIAMOND PISTONS · SPECIAL ORDER
GM LS9 / LSA forged piston kit
Build your GM LS9 / LSA rotating assembly around a Diamond 8-piston forged kit. Specify the finished bore, crown volume and gudgeon pins to suit your measured engine, fuel and intended use.
Precision in the details
- 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.
- Catalogue compression figures use a 0.040-inch head gasket; actual ratio depends on the measured engine assembly.
- Top compression ring positioned 0.250 in below the crown.
- Catalogue valve-pocket depths: 0.178 in intake / 0.108 in exhaust. Verify piston-to-valve clearance with the actual cylinder heads, camshaft and valve timing.
What your kit includes
8 forged pistons, the specified ring set, gudgeon pins and retainers. Oil-rail supports are supplied where indicated in the exact kit table.
Choose the standard gudgeon-pin kit or the H13 upgrade in the selector. Part numbers ending in -H identify the upgraded pin kit; the displayed price covers the complete piston kit with that pin specification.
Build dimensions
- Crankshaft stroke: 3.622 inch
- Connecting-rod length: 6.125 inch
- Compression height: 1.304 inch
- Gudgeon-pin diameter: 0.927 inch
- Quantity: eight pistons; rings, pins and retainers included. Oil-rail supports are included where indicated in the kit table.
Engineering reference: rings, pins and valve pockets
Ring sizes are listed as top / second / oil ring. Check pin diameter and length against your connecting-rod small end. Valve-pocket depths are catalogue dimensions; your engine builder must check piston-to-valve clearance with the actual cylinder heads, camshafts and cam timing.
| Kit SKU | Ring package | Pin diameter | Pin length | Valve-pocket depth: intake / exhaust |
|---|---|---|---|---|
| 11588-R1-8 | 1.20 mm / 1.20 mm / 3.00 mm | 0.927 in | 2.500 in | 0.178 in / 0.108 in |
| 11589-R1-8 | 1.20 mm / 1.20 mm / 3.00 mm | 0.927 in | 2.500 in | 0.178 in / 0.108 in |
| 11577-R2-8 | 1.20 mm / 1.20 mm / 3.00 mm | 0.927 in | 2.500 in | 0.176 in / 0.105 in |
| 11578-R2-8 | 1.20 mm / 1.20 mm / 3.00 mm | 0.927 in | 2.500 in | 0.176 in / 0.105 in |
| 11588-R1-8-H | 1.20 mm / 1.20 mm / 3.00 mm | 0.927 in | 2.500 in | 0.178 in / 0.108 in |
| 11589-R1-8-H | 1.20 mm / 1.20 mm / 3.00 mm | 0.927 in | 2.500 in | 0.178 in / 0.108 in |
| 11577-R2-8-H | 1.20 mm / 1.20 mm / 3.00 mm | 0.927 in | 2.500 in | 0.176 in / 0.105 in |
| 11578-R2-8-H | 1.20 mm / 1.20 mm / 3.00 mm | 0.927 in | 2.500 in | 0.176 in / 0.105 in |
A dimension marked “Not published” needs confirmation with BBT before ordering. Catalogue dimensions do not specify running clearance or ring end gap; use the instructions supplied with your exact kit.
Fitment and engine preparation
For rebuilt LS9/LSA engine combinations using the listed 3.622-inch crank stroke and 6.125-inch rods. Confirm the exact engine, sleeves, finished bore, cylinder heads and supercharged compression target; the different crown volumes are separate build choices.
The gudgeon-pin diameter for this group is 0.927 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.
View kit part numbers, bore sizes and supplied components
| Kit SKU | Bore | Crown volume | Nominal ratio | Included pin | Ring set | Ring thickness | Retainer | Oil-rail supports |
|---|---|---|---|---|---|---|---|---|
| 11588-R1-8 | 4.065 IN | -11.00 CC | 9.50:1 | G9272500185 | 09454065 | 1.20 MM x 1.20 MM x 3.00 MM | 015104-32 | No |
| 11589-R1-8 | 4.070 IN | -11.00 CC | 9.50:1 | G9272500185 | 09454070 | 1.20 MM x 1.20 MM x 3.00 MM | 015104-32 | No |
| 11577-R2-8 | 4.080 IN | -2.00 CC | 10.50:1 | G9272500185 | 09454080 | 1.20 MM x 1.20 MM x 3.00 MM | 015104-32 | No |
| 11578-R2-8 | 4.080 IN | -12.00 CC | 9.50:1 | G9272500185 | 09454080 | 1.20 MM x 1.20 MM x 3.00 MM | 015104-32 | No |
| 11588-R1-8-H | 4.065 IN | -11.00 CC | 9.50:1 | H9272500225 | 09454065 | 1.20 MM x 1.20 MM x 3.00 MM | 015104-32 | No |
| 11589-R1-8-H | 4.070 IN | -11.00 CC | 9.50:1 | H9272500225 | 09454070 | 1.20 MM x 1.20 MM x 3.00 MM | 015104-32 | No |
| 11577-R2-8-H | 4.080 IN | -2.00 CC | 10.50:1 | H9272500225 | 09454080 | 1.20 MM x 1.20 MM x 3.00 MM | 015104-32 | No |
| 11578-R2-8-H | 4.080 IN | -12.00 CC | 9.50:1 | H9272500225 | 09454080 | 1.20 MM x 1.20 MM x 3.00 MM | 015104-32 | No |
Use the option selectors to choose your order. Compression ratios are nominal catalogue figures; the final ratio depends on the measured chamber, deck and gasket volumes.
Made to order · delivery
Allow approximately 5–6 weeks for delivery, pending Australian customs processing time. Manufacturing schedules, international freight and customs clearance may extend this estimate. Contact BBT before ordering for a build with a fixed deadline.
Plan your build with BBT
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.
LS9 engine parts | LSA engine parts
Photography shows a representative Diamond piston design. Crown shape, valve pockets, skirt finish and supplied components vary with the selected part number.