LM4 Rebuild Kit
5.3L aluminum, Gen III (2003–2005 SSR / Trailblazer EXT). Every kit below is spec'd for the LM4 specifically — not a one-size "LS1/LQ4/5.3" overhaul set — and every part is checked against the others before it ships.
★★★★★ 5.0 · 20 Google reviews · Bullet LSX Engines, Glendale AZ · 602-510-9021
Build my LM4 kitHave us build the engineWhat's specific to the LM4
- Ring set matched to your grooves: Mahle Original Premium ring set, standard 3.780" bore — 1.5 / 1.5 / 3.0mm, plasma-moly (4.8 / 5.3).
- Cathedral port heads, ~61cc chambers. Cams, pistons (valve-pocket angle) and rockers are matched to the port — a cathedral-port grind is the baseline.
- 24x crank reluctor. Any replacement crank or timing set keeps the signal your computer expects.
- Factory 6.098" rods. Forged-rod kits use 6.125" rods with pistons to match — we pair them so deck clearance comes out right.
- Aluminum block. Overbore to 3.905".
| Displacement | Bore × stroke | Block | Heads | Max overbore |
|---|---|---|---|---|
| 5.3L / 325 ci | 3.780" × 3.622" | Aluminum, Gen III | cathedral port, 61cc | 3.905" |
LM4 kits and prices
Prices are live from our builder. Open any kit in the builder to swap parts — every change is re-checked for fit.
LM4 Refresh kit$1,115
Main, rod and cam bearings, a standard-bore ring set matched to your ring grooves, full gasket set, crank seals, oil pump and timing set — for an engine that measures in spec and needs no machining. · 10.1:1
What's in it (10 parts)
| Part | Brand / part # | Price |
|---|---|---|
| Main Bearings King SI Series Main Bearing Set, LS Gen III/IV, Standard | King Bearings · KIB-MB5293SI | $40 |
| Rod Bearings King SI Series Rod Bearing Set, LS, Standard (8) | King Bearings · KIB-CR807-SI | $29 |
| Cam Bearings Dura-Bond CHP-25 High Performance Cam Bearing Set, Gen IV LS | Dura-Bond · DUR-CHP25 | $55 |
| Piston Rings Mahle Original Premium ring set, standard 3.780" bore — 1.5 / 1.5 / 3.0mm, plasma-moly (4.8 / 5.3) | Mahle · MAH-41859CP | $66 |
| Gaskets & Seals Texas Speed gasket kit — 4.8 / 5.3 / 5.7 Gen III cathedral: head, intake, timing cover, oil pan, valley, water pump & valve cover gaskets, TSP front seal + GM rear cover with rear main seal | Texas Speed & Performance · TSP-KIT-G3-53 | $460 |
| Crank Seals Front & rear main seals — included in your gasket set (Texas Speed kit: TSP front seal + GM rear cover with seal) | Included · SEALS-GASKETSET | incl. |
| Timing Set Rollmaster LS1 Single-Roller Timing Set, 1x, 3-bolt cam | Rollmaster · ROL-NA-CS1135 | $158 |
| Oil Pump Melling High Pressure Oil Pump, 97+ LS | Melling · MEL-10295 | $156 |
| Assembly Lube, Plastigage & Break-in Oil Assembly supplies: Royal Purple Max-Tuff Assembly Lube + Plastigage green (.001"–.003"), 2 strips + Driven BR30 5W-30 Break-In Oil, 6 quarts | Royal Purple / Sealed Power / Driven Racing · RYP-41330, SLP-SPG1-2, DRV-01806-6 | $107 |
| Required GM 12588670 LS2 timing chain dampener (GM-12588670) — the tensioner for every non-VVT timing set; early Gen III blocks may need the mounting boss drilled/tapped | $44 |
Refresh kit: check bearing clearances, ring end gaps and cam/lifter wear at install — parts are standard size for an engine that doesn't need machining
LM4 Refresh + cam kit$2,249
Everything in the refresh kit plus a cam picked for your heads, valve springs, lifters, pushrods and a rocker trunnion upgrade. · est. 405 hp · 10.1:1
What's in it (15 parts)
| Part | Brand / part # | Price |
|---|---|---|
| Main Bearings King SI Series Main Bearing Set, LS Gen III/IV, Standard | King Bearings · KIB-MB5293SI | $40 |
| Rod Bearings King SI Series Rod Bearing Set, LS, Standard (8) | King Bearings · KIB-CR807-SI | $29 |
| Cam Bearings Dura-Bond CHP-25 High Performance Cam Bearing Set, Gen IV LS | Dura-Bond · DUR-CHP25 | $55 |
| Piston Rings Mahle Original Premium ring set, standard 3.780" bore — 1.5 / 1.5 / 3.0mm, plasma-moly (4.8 / 5.3) | Mahle · MAH-41859CP | $66 |
| Gaskets & Seals Texas Speed gasket kit — 4.8 / 5.3 / 5.7 Gen III cathedral: head, intake, timing cover, oil pan, valley, water pump & valve cover gaskets, TSP front seal + GM rear cover with rear main seal | Texas Speed & Performance · TSP-KIT-G3-53 | $460 |
| Crank Seals Front & rear main seals — included in your gasket set (Texas Speed kit: TSP front seal + GM rear cover with seal) | Included · SEALS-GASKETSET | incl. |
| Camshaft TSP Stage 1 Low Lift Truck Camshaft, 208/214 .550"/.550" 112 LSA | Texas Speed & Performance · TSP-LL208214112 | $420 |
| Valve Spring Kit TSP VS2225 .625" LS Beehive Valve Springs (16) — uses your stock retainers & locks | Texas Speed & Performance · TSP-VS2225-16 | $227 |
| Timing Set Rollmaster LS1 Single-Roller Timing Set, 1x, 3-bolt cam | Rollmaster · ROL-NA-CS1135 | $158 |
| Lifters GM/Delphi LS7-Style Lifters, Set of 16 | GM · DEL-25341990-16 | $210 |
| Pushrods TSP 7.400" 5/16" chromoly pushrods, Set of 16 — standard LS length | Texas Speed & Performance · TSP-7400-16 | $127 |
| Rocker Arms TSP trunnion upgrade kit for your stock GM rockers (LS / LT) — you or your shop press them in | Texas Speed & Performance · TSP-TrunnionUpgrade | $150 |
| Oil Pump Melling High Pressure Oil Pump, 97+ LS | Melling · MEL-10295 | $156 |
| Assembly Lube, Plastigage & Break-in Oil Assembly supplies: Royal Purple Max-Tuff Assembly Lube + Plastigage green (.001"–.003"), 2 strips + Driven BR30 5W-30 Break-In Oil, 6 quarts | Royal Purple / Sealed Power / Driven Racing · RYP-41330, SLP-SPG1-2, DRV-01806-6 | $107 |
| Required GM 12588670 LS2 timing chain dampener (GM-12588670) — the tensioner for every non-VVT timing set; early Gen III blocks may need the mounting boss drilled/tapped | $44 |
Refresh kit: check bearing clearances, ring end gaps and cam/lifter wear at install — parts are standard size for an engine that doesn't need machining
LM4 Rebuild parts kit$1,329
For a block that gets machined: everything to rebuild it at stock power, with a spec sheet for your machine shop. Keeps your crank, rods, pistons and heads. · est. 355 hp · 10:1
What's in it (19 parts)
| Part | Brand / part # | Price |
|---|---|---|
| Main Bearings King SI Series Main Bearing Set, LS Gen III/IV, Standard | King Bearings · KIB-MB5293SI | $40 |
| Rod Bearings King SI Series Rod Bearing Set, LS, Standard (8) | King Bearings · KIB-CR807-SI | $29 |
| Cam Bearings Dura-Bond CHP-25 High Performance Cam Bearing Set, Gen IV LS | Dura-Bond · DUR-CHP25 | $55 |
| Piston Rings Mahle Original Premium ring set, standard 3.780" bore — 1.5 / 1.5 / 3.0mm, plasma-moly (4.8 / 5.3) | Mahle · MAH-41859CP | $66 |
| Crank Seals TSP front crank seal — rear main seal comes installed in your new GM rear cover | Texas Speed & Performance · TSP-FCS-ONLY | $20 |
| Block Plugs Summit LS Block Plug Kit — threaded coolant & oil plugs, oil plug & barbell, Gen III/IV (SUM-G1584) | Summit Racing · SUM-G1584 | $18 |
| Head Gaskets TSP OE-Style LS1/LS6 Head Gasket .051", 3.920" Bore (pair) | Texas Speed & Performance · TSP-HG9226 | $80 |
| Head Studs / Bolts TSP Gen IV Cylinder Head Bolt Kit | Texas Speed & Performance · TSP-HB0568-KIT | $80 |
| Valve Spring Kit No spring kit needed — your cam runs the factory valve springs | Bullet LSX Engines · NO-SPRING-KIT | incl. |
| Cam Retainer Plate TSP LS Camshaft Retainer Plate & Bolts Kit | Texas Speed & Performance · TSP-CP9016 | $28 |
| Timing Set Rollmaster LS1 Single-Roller Timing Set, 1x, 3-bolt cam | Rollmaster · ROL-NA-CS1135 | $158 |
| Lifter Trays GM LS2/LS3/LS7/L98 Lifter Trays (set of 4) | GM · GM-12595365-4 | $49 |
| Rocker Arms TSP trunnion upgrade kit for your stock GM rockers (LS / LT) — you or your shop press them in | Texas Speed & Performance · TSP-TrunnionUpgrade | $150 |
| Oil Filter ACDelco PF48 Oil Filter — standard LS, fits every LS block | ACDelco · ACD-PF48 | $9 |
| Oil Pump Melling High Pressure Oil Pump, 97+ LS | Melling · MEL-10295 | $156 |
| Rear Main Cover GM LS Rear Cover Assembly — new plate with rear main seal, gasket & bolts (LS1/LS2/LS3/LS6/LS7) | GM · GM-12639250 | $80 |
| Cover Gaskets Cover gaskets: LS valve cover gaskets (pair) + Gen III valley cover gasket set + LS timing cover gasket + LS oil pan gasket (upper pan to block) | Cometic / Texas Speed & Performance · CometicValveCoverGasket, TSPValleyCoverGasket, CometicLSTimingCoverGasket, COM-C5173 | $160 |
| Assembly Lube, Plastigage & Break-in Oil Assembly supplies: Royal Purple Max-Tuff Assembly Lube + Plastigage green (.001"–.003"), 2 strips + Driven BR30 5W-30 Break-In Oil, 6 quarts | Royal Purple / Sealed Power / Driven Racing · RYP-41330, SLP-SPG1-2, DRV-01806-6 | $107 |
| Required GM 12588670 LS2 timing chain dampener (GM-12588670) — the tensioner for every non-VVT timing set; early Gen III blocks may need the mounting boss drilled/tapped | $44 |
Re-used from your engine: Crankshaft, Connecting Rods, Pistons, Cylinder Heads, Camshaft, Lifters, Pushrods, Oil Pan Package, Valley Cover, Timing Cover, Valve Covers, Harmonic Balancer.
Gen III head bolt/stud length depends on block year: 2003 & earlier blocks use 8 long + 2 short bolts per head, 2004+ use 10 equal-length. Count your bolts before ordering — if 8 are longer, pick the 1997–2003 kit
LM4 Forged bottom-end kit$4,174
Your crank with forged rods and forged pistons, bearings, rings, gaskets and oiling — ready for a big cam or boost. · est. 445 hp · 11.1:1
What's in it (23 parts)
| Part | Brand / part # | Price |
|---|---|---|
| Main Bearings Clevite P-Series Main Bearing Set MS-2199P, LS Gen III/IV, Standard | Clevite · Clevite P series main LS | $108 |
| Connecting Rods Summit Racing Pro LS H-Beam 6.125" Rods, .927" floating pin, ARP 2000 bolts, stroker clearanced, Set of 8 | Summit Racing · SUM-LS6125927 | $700 |
| Rod Bearings Clevite P-Series Rod Bearing Set CB-663P(8), LS, Standard | Clevite · Clevite P series rod LS | $38 |
| Pistons CP-Carrillo Bullet LS Piston Set (8) — 3.799" bore, 3.622" stroke, 6.125" rod, +5cc dome, pins & steel top-ring set | CP-Carrillo · BLS1017-019 | $1,016 |
| Cam Bearings Dura-Bond CHP-25 High Performance Cam Bearing Set, Gen IV LS | Dura-Bond · DUR-CHP25 | $55 |
| Crank Seals TSP front crank seal — rear main seal comes installed in your new GM rear cover | Texas Speed & Performance · TSP-FCS-ONLY | $20 |
| Block Plugs Summit LS Block Plug Kit — threaded coolant & oil plugs, oil plug & barbell, Gen III/IV (SUM-G1584) | Summit Racing · SUM-G1584 | $18 |
| Head Gaskets TSP OE-Style LS1/LS6 Head Gasket .051", 3.920" Bore (pair) | Texas Speed & Performance · TSP-HG9226 | $80 |
| Head Studs / Bolts TSP Gen IV Cylinder Head Bolt Kit | Texas Speed & Performance · TSP-HB0568-KIT | $80 |
| Camshaft TSP Stage 1 Cathedral N/A Camshaft, 216/232 .600"/.600" 112 LSA | Texas Speed & Performance · TSP-Cath-NA-Stage1 | $420 |
| Valve Spring Kit TSP .660" Polished Dual Spring Kit — PAC springs, titanium retainers, PRC integrated seat/seals (16) | Texas Speed & Performance · TSP-PACPOL660SPRINGKIT | $360 |
| Cam Retainer Plate TSP LS Camshaft Retainer Plate & Bolts Kit | Texas Speed & Performance · TSP-CP9016 | $28 |
| Timing Set Rollmaster LS1 Single-Roller Timing Set, 1x, 3-bolt cam | Rollmaster · ROL-NA-CS1135 | $158 |
| Lifters GM/Delphi LS7-Style Lifters, Set of 16 | GM · DEL-25341990-16 | $210 |
| Lifter Trays GM LS2/LS3/LS7/L98 Lifter Trays (set of 4) | GM · GM-12595365-4 | $49 |
| Pushrods TSP 7.400" 5/16" chromoly pushrods, Set of 16 — standard LS length | Texas Speed & Performance · TSP-7400-16 | $127 |
| Rocker Arms TSP trunnion upgrade kit for your stock GM rockers (LS / LT) — you or your shop press them in | Texas Speed & Performance · TSP-TrunnionUpgrade | $150 |
| Oil Filter ACDelco PF48 Oil Filter — standard LS, fits every LS block | ACDelco · ACD-PF48 | $9 |
| Oil Pump Melling High Pressure Oil Pump, 97+ LS | Melling · MEL-10295 | $156 |
| Rear Main Cover GM LS Rear Cover Assembly — new plate with rear main seal, gasket & bolts (LS1/LS2/LS3/LS6/LS7) | GM · GM-12639250 | $80 |
| Cover Gaskets Cover gaskets: LS valve cover gaskets (pair) + Gen III valley cover gasket set + LS timing cover gasket + LS oil pan gasket (upper pan to block) | Cometic / Texas Speed & Performance · CometicValveCoverGasket, TSPValleyCoverGasket, CometicLSTimingCoverGasket, COM-C5173 | $160 |
| Assembly Lube, Plastigage & Break-in Oil Assembly supplies: Royal Purple Max-Tuff Assembly Lube + Plastigage green (.001"–.003"), 2 strips + Driven BR30 5W-30 Break-In Oil, 6 quarts | Royal Purple / Sealed Power / Driven Racing · RYP-41330, SLP-SPG1-2, DRV-01806-6 | $107 |
| Required GM 12588670 LS2 timing chain dampener (GM-12588670) — the tensioner for every non-VVT timing set; early Gen III blocks may need the mounting boss drilled/tapped | $44 |
Re-used from your engine: Crankshaft, Cylinder Heads, Oil Pan Package, Valley Cover, Timing Cover, Valve Covers, Harmonic Balancer.
Estimated 445 hp — short of your goal; step up heads/cam or displacement
Gen III head bolt/stud length depends on block year: 2003 & earlier blocks use 8 long + 2 short bolts per head, 2004+ use 10 equal-length. Count your bolts before ordering — if 8 are longer, pick the 1997–2003 kit
Pistons are 3.799" — your machine shop bores and hones the block to match (not part of this kit)
LM4 Stroker kit$6,601
Forged 4.000" crank (4.125" on the LS7), forged rods and pistons, bearings, gaskets and oiling — the most cubic inches your block takes. · est. 570 hp · 11.5:1
What's in it (26 parts)
| Part | Brand / part # | Price |
|---|---|---|
| Crankshaft TSP 4340 Forged LS Crankshaft, 4.000" Stroke, 2.100" Pin, 6-Bolt, Wet Sump | Texas Speed & Performance · TSP-4002100WR-X | $969 |
| Main Bearings King XP Series Main Bearing Set, LS Gen III/IV, Standard | King Bearings · KIB-MB5013XP | $126 |
| Connecting Rods Summit Racing Pro LS H-Beam 6.125" Rods, .927" floating pin, ARP 2000 bolts, stroker clearanced, Set of 8 | Summit Racing · SUM-LS6125927 | $700 |
| Rod Bearings King XP Series Rod Bearing Set, LS, Standard (8) | King Bearings · KIB-CR807XPN | $70 |
| Pistons CP-Carrillo Bullet LS Piston Set (8) — 3.905" bore, 4.000" stroke, 6.125" rod, -2.7cc flat top, pins & steel top-ring set | CP-Carrillo · BLS1009-007 | $956 |
| Cam Bearings Dura-Bond CHP-25 High Performance Cam Bearing Set, Gen IV LS | Dura-Bond · DUR-CHP25 | $55 |
| Crank Seals TSP front crank seal — rear main seal comes installed in your new GM rear cover | Texas Speed & Performance · TSP-FCS-ONLY | $20 |
| Block Plugs Summit LS Block Plug Kit — threaded coolant & oil plugs, oil plug & barbell, Gen III/IV (SUM-G1584) | Summit Racing · SUM-G1584 | $18 |
| Head Gaskets TSP OE-Style LS1/LS6 Head Gasket .051", 3.920" Bore (pair) | Texas Speed & Performance · TSP-HG9226 | $80 |
| Head Studs / Bolts TSP Gen IV Cylinder Head Bolt Kit | Texas Speed & Performance · TSP-HB0568-KIT | $80 |
| Camshaft TSP Cleetus McFarland "Bald Eagle" LS1/LS2 N/A Cam | Texas Speed & Performance · TSP-CATHBaldEagle-NA | $420 |
| Valve Spring Kit PAC 1219 Beehive LS Valve Springs (16) — uses your stock retainers & locks | PAC · PAC-1219 | $230 |
| Cam Retainer Plate TSP LS Camshaft Retainer Plate & Bolts Kit | Texas Speed & Performance · TSP-CP9016 | $28 |
| Timing Set Rollmaster LS1 Single-Roller Timing Set, 1x, 3-bolt cam | Rollmaster · ROL-NA-CS1135 | $158 |
| Lifters GM/Delphi LS7-Style Lifters, Set of 16 | GM · DEL-25341990-16 | $210 |
| Lifter Trays GM LS2/LS3/LS7/L98 Lifter Trays (set of 4) | GM · GM-12595365-4 | $49 |
| Pushrods TSP 7.400" 5/16" chromoly pushrods, Set of 16 — standard LS length | Texas Speed & Performance · TSP-7400-16 | $127 |
| Rocker Arms TSP trunnion upgrade kit for your stock GM rockers (LS / LT) — you or your shop press them in | Texas Speed & Performance · TSP-TrunnionUpgrade | $150 |
| Oil Filter ACDelco PF48 Oil Filter — standard LS, fits every LS block | ACDelco · ACD-PF48 | $9 |
| Oil Pump Melling High Pressure Oil Pump, 97+ LS | Melling · MEL-10295 | $156 |
| Oil Control — Baffle, Windage Tray & Crank Scraper Improved Racing EGM-241 aluminum windage tray — clears up to a 4.000" stroke with factory or aftermarket rods; most factory LS pans, GM retro-fit pan and Holley 302-1; factory or ARP main studs | Improved Racing · IRP-EGM-241 | $149 |
| Rear Main Cover GM LS Rear Cover Assembly — new plate with rear main seal, gasket & bolts (LS1/LS2/LS3/LS6/LS7) | GM · GM-12639250 | $80 |
| Cover Gaskets Cover gaskets: LS valve cover gaskets (pair) + Gen III valley cover gasket set + LS timing cover gasket + LS oil pan gasket (upper pan to block) | Cometic / Texas Speed & Performance · CometicValveCoverGasket, TSPValleyCoverGasket, CometicLSTimingCoverGasket, COM-C5173 | $160 |
| Assembly Lube, Plastigage & Break-in Oil Assembly supplies: Royal Purple Max-Tuff Assembly Lube + Plastigage green (.001"–.003"), 2 strips + Driven BR30 5W-30 Break-In Oil, 6 quarts | Royal Purple / Sealed Power / Driven Racing · RYP-41330, SLP-SPG1-2, DRV-01806-6 | $107 |
| Required PRC CNC porting of core heads (cathedral port) [PRC LS6 Porting Service] — mail-in, heads ship to PRC | $1,450 | |
| Required GM 12588670 LS2 timing chain dampener (GM-12588670) — the tensioner for every non-VVT timing set; early Gen III blocks may need the mounting boss drilled/tapped | $44 |
Re-used from your engine: Cylinder Heads, Oil Pan Package, Valley Cover, Timing Cover, Valve Covers, Harmonic Balancer.
Gen III head bolt/stud length depends on block year: 2003 & earlier blocks use 8 long + 2 short bolts per head, 2004+ use 10 equal-length. Count your bolts before ordering — if 8 are longer, pick the 1997–2003 kit
Pistons are 3.905" — your machine shop bores and hones the block to match (not part of this kit)
Questions
Main, rod and cam bearings, a standard-bore ring set matched to the LM4's ring grooves, a full gasket set, crank seals, an oil pump and a timing set. Anything you want to keep — covers, oil pan, balancer — you mark "re-use mine" at no charge.
Mahle Original Premium ring set, standard 3.780" bore — 1.5 / 1.5 / 3.0mm, plasma-moly (4.8 / 5.3)
Yes — every kit drop-ships from our suppliers and comes with a machine-shop spec sheet (bore, deck, clearances) and assembly torque specs. Or have Bullet LSX Engines machine and build it in Glendale, AZ.
It's on the Service Parts Identification sticker (glove box, console lid or spare-tire cover), or match the 8th digit of the VIN.