{"product_id":"diamond-special-order-gm-ls1-based-custom-bore-4-000-stroke-6-125-rod-1-115-ch","title":"Diamond Forged Pistons - GM LS1-based custom-bore - 4.000 in Stroke, 6.125 in Rod","description":"\u003ch2\u003eDiamond forged pistons for GM LS1-based custom-bore\u003c\/h2\u003e\u003cp\u003eEight-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.\u003c\/p\u003e\u003cp\u003e\u003cem\u003eRepresentative Diamond catalogue photograph. Crown shape, valve reliefs, skirt finish and supplied components may differ by the selected part number.\u003c\/em\u003e\u003c\/p\u003e\u003ch3\u003eMade to order and delivery\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eSpecial-order, made-to-order pistons. Allow approximately 5–6 weeks for delivery, pending Australian customs processing time.\u003c\/strong\u003e Manufacturing schedules, international freight and clearance can extend this estimate.\u003c\/p\u003e\u003ch3\u003eFeatures and included components\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eForged 2618 aluminium construction, machined in the USA.\u003c\/li\u003e\n\u003cli\u003eMachined crown and valve-relief profiles; verify the chosen cylinder head and camshaft combination.\u003c\/li\u003e\n\u003cli\u003eOffset pins and moly-coated skirts.\u003c\/li\u003e\n\u003cli\u003eTrend gudgeon pins, the listed ring set and pin retainers included.\u003c\/li\u003e\n\u003cli\u003eStandard-pin and upgraded H13 kits available as separately priced options.\u003c\/li\u003e\n\u003cli\u003eCatalogue compression figures use a 0.040-inch head gasket; actual ratio depends on the measured engine assembly.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eBuild dimensions\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eCrankshaft stroke: 4.000 inch\u003c\/li\u003e\n\u003cli\u003eConnecting-rod length: 6.125 inch\u003c\/li\u003e\n\u003cli\u003eCompression height: 1.115 inch\u003c\/li\u003e\n\u003cli\u003eGudgeon-pin diameter: 0.927 inch\u003c\/li\u003e\n\u003cli\u003eQuantity: eight pistons; rings, pins and retainers included. Oil-rail supports are included where indicated in the kit table.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eKit selection\u003c\/h3\u003e\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eKit SKU\u003c\/th\u003e\n\u003cth\u003eBore\u003c\/th\u003e\n\u003cth\u003eCrown volume\u003c\/th\u003e\n\u003cth\u003eNominal ratio\u003c\/th\u003e\n\u003cth\u003eIncluded pin\u003c\/th\u003e\n\u003cth\u003eRing set\u003c\/th\u003e\n\u003cth\u003eRing thickness\u003c\/th\u003e\n\u003cth\u003eRetainer\u003c\/th\u003e\n\u003cth\u003eOil-rail supports\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e11518-R1-8\u003c\/td\u003e\n\u003ctd\u003e4.000 IN\u003c\/td\u003e\n\u003ctd\u003e-2.00 CC\u003c\/td\u003e\n\u003ctd\u003e11.10:1\u003c\/td\u003e\n\u003ctd\u003eG9272500185\u003c\/td\u003e\n\u003ctd\u003e09454005\u003c\/td\u003e\n\u003ctd\u003e1.20 MM x 1.20 MM x 3.00 MM\u003c\/td\u003e\n\u003ctd\u003e015104-32\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e11520-R1-8\u003c\/td\u003e\n\u003ctd\u003e4.000 IN\u003c\/td\u003e\n\u003ctd\u003e-15.00 CC\u003c\/td\u003e\n\u003ctd\u003e9.70:1\u003c\/td\u003e\n\u003ctd\u003eG9272500185\u003c\/td\u003e\n\u003ctd\u003e09454005\u003c\/td\u003e\n\u003ctd\u003e1.20 MM x 1.20 MM x 3.00 MM\u003c\/td\u003e\n\u003ctd\u003e015104-32\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e11521-R1-8\u003c\/td\u003e\n\u003ctd\u003e4.030 IN\u003c\/td\u003e\n\u003ctd\u003e-15.00 CC\u003c\/td\u003e\n\u003ctd\u003e9.80:1\u003c\/td\u003e\n\u003ctd\u003eG9272500185\u003c\/td\u003e\n\u003ctd\u003e09454030\u003c\/td\u003e\n\u003ctd\u003e1.20 MM x 1.20 MM x 3.00 MM\u003c\/td\u003e\n\u003ctd\u003e015104-32\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e11522-R1-8\u003c\/td\u003e\n\u003ctd\u003e4.125 IN\u003c\/td\u003e\n\u003ctd\u003e-7.00 CC\u003c\/td\u003e\n\u003ctd\u003e11.10:1\u003c\/td\u003e\n\u003ctd\u003eG9272500185\u003c\/td\u003e\n\u003ctd\u003e09454065\u003c\/td\u003e\n\u003ctd\u003e1.20 MM x 1.20 MM x 3.00 MM\u003c\/td\u003e\n\u003ctd\u003e015104-32\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e11518-R1-8-H\u003c\/td\u003e\n\u003ctd\u003e4.000 IN\u003c\/td\u003e\n\u003ctd\u003e-2.00 CC\u003c\/td\u003e\n\u003ctd\u003e11.10:1\u003c\/td\u003e\n\u003ctd\u003eH9272500225\u003c\/td\u003e\n\u003ctd\u003e09454005\u003c\/td\u003e\n\u003ctd\u003e1.20 MM x 1.20 MM x 3.00 MM\u003c\/td\u003e\n\u003ctd\u003e015104-32\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e11520-R1-8-H\u003c\/td\u003e\n\u003ctd\u003e4.000 IN\u003c\/td\u003e\n\u003ctd\u003e-15.00 CC\u003c\/td\u003e\n\u003ctd\u003e9.70:1\u003c\/td\u003e\n\u003ctd\u003eH9272500225\u003c\/td\u003e\n\u003ctd\u003e09454005\u003c\/td\u003e\n\u003ctd\u003e1.20 MM x 1.20 MM x 3.00 MM\u003c\/td\u003e\n\u003ctd\u003e015104-32\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e11521-R1-8-H\u003c\/td\u003e\n\u003ctd\u003e4.030 IN\u003c\/td\u003e\n\u003ctd\u003e-15.00 CC\u003c\/td\u003e\n\u003ctd\u003e9.80:1\u003c\/td\u003e\n\u003ctd\u003eH9272500225\u003c\/td\u003e\n\u003ctd\u003e09454030\u003c\/td\u003e\n\u003ctd\u003e1.20 MM x 1.20 MM x 3.00 MM\u003c\/td\u003e\n\u003ctd\u003e015104-32\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e11522-R1-8-H\u003c\/td\u003e\n\u003ctd\u003e4.125 IN\u003c\/td\u003e\n\u003ctd\u003e-7.00 CC\u003c\/td\u003e\n\u003ctd\u003e11.10:1\u003c\/td\u003e\n\u003ctd\u003eH9272500225\u003c\/td\u003e\n\u003ctd\u003e09454065\u003c\/td\u003e\n\u003ctd\u003e1.20 MM x 1.20 MM x 3.00 MM\u003c\/td\u003e\n\u003ctd\u003e015104-32\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch3\u003eFitment and installation\u003c\/h3\u003e\u003cp\u003eFor LS1-based engine builds with suitable sleeves or an aftermarket block. The listed 4.000-inch and larger bores must not be treated as a routine overbore of a production 5.7-litre LS1 block. Confirm the block and cylinder-head combination before ordering.\u003c\/p\u003e\u003cp\u003eRequires a 4.000-inch stroker crankshaft and the listed 6.125-inch rods. This is not a standard-stroke replacement piston.\u003c\/p\u003e\u003cp\u003eThe 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.\u003c\/p\u003e\u003cp\u003eHave 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.\u003c\/p\u003e\u003ch3\u003eBBT workshop support and related parts\u003c\/h3\u003e\u003cp\u003eBoost \u0026amp; 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.\u003c\/p\u003e\u003cp\u003e\u003ca href=\"\/collections\/bt-fit-engine-ls1\"\u003eLS1 engine parts\u003c\/a\u003e\u003c\/p\u003e","brand":"Diamond Pistons","offers":[{"title":"4.000 in \/ -2.00 cc \/ 11.10:1 nominal \/ Standard G-series","offer_id":67607064313923,"sku":"11518-R1-8","price":2460.0,"currency_code":"AUD","in_stock":true},{"title":"4.000 in \/ -15.00 cc \/ 9.70:1 nominal \/ Standard G-series","offer_id":67607064346691,"sku":"11520-R1-8","price":2460.0,"currency_code":"AUD","in_stock":true},{"title":"4.030 in \/ -15.00 cc \/ 9.80:1 nominal \/ Standard G-series","offer_id":67607064379459,"sku":"11521-R1-8","price":2460.0,"currency_code":"AUD","in_stock":true},{"title":"4.125 in \/ -7.00 cc \/ 11.10:1 nominal \/ Standard G-series","offer_id":67607064412227,"sku":"11522-R1-8","price":2460.0,"currency_code":"AUD","in_stock":true},{"title":"4.000 in \/ -2.00 cc \/ 11.10:1 nominal \/ H13 upgrade","offer_id":67607064444995,"sku":"11518-R1-8-H","price":2653.0,"currency_code":"AUD","in_stock":true},{"title":"4.000 in \/ -15.00 cc \/ 9.70:1 nominal \/ H13 upgrade","offer_id":67607064477763,"sku":"11520-R1-8-H","price":2653.0,"currency_code":"AUD","in_stock":true},{"title":"4.030 in \/ -15.00 cc \/ 9.80:1 nominal \/ H13 upgrade","offer_id":67607064510531,"sku":"11521-R1-8-H","price":2653.0,"currency_code":"AUD","in_stock":true},{"title":"4.125 in \/ -7.00 cc \/ 11.10:1 nominal \/ H13 upgrade","offer_id":67607064543299,"sku":"11522-R1-8-H","price":2653.0,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0703\/0659\/4883\/files\/F26084_5218.jpg?v=1791010502","url":"https:\/\/builtbyboostandtune.com.au\/products\/diamond-special-order-gm-ls1-based-custom-bore-4-000-stroke-6-125-rod-1-115-ch","provider":"BUILT BY BOOST AND TUNE","version":"1.0","type":"link"}