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The JE Pistons Ultra Series forged piston set for GM Gen III/IV LS V8 engines gives your performance engine build a durable foundation for demanding use. Forged from 2618 aluminum, these Ultra Series pistons combine JE's application-specific engineering with features developed for demanding performance builds. This kit pairs an FSR forging with lateral gas ports, an accumulator groove, skirt coating, and Thermal Crown treatment. Carefully machined crown geometry, ring grooves, and pin bores bring those features together in a piston designed around its engine application. This 4.125 in bore kit uses a 1.115 in compression height and is supplied as a matched set of eight pistons for your next V8 build.
| Specification | Details |
|---|---|
| Brand | JE Pistons |
| Piston Series | JE Ultra Series |
| Manufacturer Part Number | 361731 |
| SKU | JEP361731 |
| UPC | 193564038395 |
| Application | GM Gen III/IV LS V8 engines |
| Piston Quantity | 8 |
| Package | Set of 8 pistons |
| Bore Diameter | 4.125 in |
| OEM Bore Diameter | 4.125 in |
| Oversized | No |
| Oversize Amount | Standard |
| Compression Height | 1.115 in |
| Crown Design | Inverted Dome / Dish |
| Crown Volume | -17.40 cc |
| Piston Alloy | 2618 forged aluminum |
| Forging Type | FSR |
| Cylinder Head | LS 12°/15° combination valve reliefs |
| Engine Make | Chevrolet |
| Engine Architecture | LSX |
| Engine Family | LS |
| Engine Displacement — Reference Build | 427 cu in |
| Connecting Rod Length | 6.125 in |
| Engine Stroke | 4.000 in |
| Deck Height | 9.240 in |
| Ring Set Included | No |
| Recommended Ring Set | JG31F8-4125-2 |
| Add-On Part Number | JG31F8-4125-2 |
| Ring Set Thickness | 1.20 mm x 1.50 mm x 3.00 mm |
| Top Compression Ring Thickness | 0.0475 in |
| Second Compression Ring Thickness | 0.0600 in |
| Oil Ring Thickness | 0.1490 in |
| Top Ring Groove Width | 0.04750 in |
| Second Ring Groove Width | 0.06000 in |
| Oil Ring Groove Width | 0.15000 in |
| Wrist Pin Included | Yes |
| Wrist Pin Part Number | 927-2250-15-51C |
| Wrist Pin Material | 9310 Nickel Carbon Steel Alloy |
| Wrist Pin Outer Diameter | 0.927 in |
| Wrist Pin Length | 2.250 in |
| Wrist Pin Wall Thickness | 0.200 in |
| Wrist Pin Retainer Included | Yes |
| Wrist Pin Retainer Part Number | 927-073-MW |
| Pro Seal Head Gasket Part Number | GM1005-051 |
| Intake Angle | 12° |
| Intake Diameter | 2.450 in |
| Intake Depth | 0.235 in |
| Exhaust Angle | 12° |
| Exhaust Diameter | 2.000 in |
| Compression Ratio — 64cc Head | 10.40:1 |
| Product Type | Engine Piston Kit |
| Engine Type | Internal combustion |
| Piston Sub-Series | LS Inverted Dome |
| Skirt Coating | Yes |
| Smooth Crown Finish | No |
| Thermal Crown | Yes |
| Tuff Skirt | No |
| Ultra Dome | No |
| Ultra Groove | No |
| Ultra Groove Plus Gas Port | No |
| Vertical Gas Ports | No |
| Combo 2 | No |
| Anodized Top Ring Groove | No |
| Accumulator Groove | Yes |
| 3D Undercrown Milling | No |
| Contact Reduction | No |
| Double Pin Oilers | Yes |
| DVGP | No |
| Econo Undercrown Milling | No |
| EN Plating | No |
| Gas Distribution | No |
| Lateral Gas Ports | Yes |
| Mill Undercrown | No |
| Pin Fit | Yes |
