Katech LT1/LT4 Billet Steel Main Caps #KAT-A6985
Build the foundation before you build the boost.
Forged pistons and rods are only part of a strong bottom end. The main caps help hold the crankshaft’s bearings in position, and maintaining that support becomes increasingly important as cylinder pressure and engine speed rise.
The Katech KAT-A6985 main cap set combines billet steel construction with LS7/LS9-style steel locating dowels for compatible Gen V LT1 and LT4 blocks. Designed for performance engine builds, this upgrade addresses both cap strength and the way the caps locate within the block.
Strength and positive location
Main caps form the lower half of the crankshaft’s main bearing housings. Combustion forces and rotating-assembly inertia load these housings repeatedly during engine operation.
From an engineering standpoint, movement or distortion at this joint can affect bearing housing geometry and the bearing’s operating conditions. The objective is to keep the assembled main bearing tunnel stable, correctly sized, and aligned.
Katech’s design uses two steel locating dowels per cap, rather than relying on the factory block’s aluminum register walls for lateral location. The dowels establish a positive locating interface; the main fasteners provide the clamping load that holds the assembly together.
Suggested ARP main stud upgrade #234-5802
Griffin Motorsports recommends choosing the ARP 234-5802 main stud kit when planning this conversion. ARP specifies 8740 chromoly steel, heat-treated to a 190,000 psi tensile-strength rating, for its main studs. The kit includes main studs, nuts, washers, and side bolts.
Studs remain seated in the block while the nuts are tightened, helping provide more consistent assembly preload and reducing repeated installation wear on the block threads.
Select your final fasteners before machining. Changing fasteners or assembly preload can change main bearing housing dimensions. Final machining must use the same fasteners, lubricant, and specified preload intended for engine assembly. Block machining and align boring/honing required.
Product Specifications
Katech part number: KAT-A6985
Application: Compatible Gen V LT1 and LT4 engine blocks
Cap material: Billet steel
Includes: Five main caps and steel locating dowels
Locating arrangement: Two LS7/LS9-style steel dowels per cap
Optional fastener upgrade: ARP 234-5802 main stud kit
Installation: Block machining and align boring/honing required
Vehicle Applications
2014–2019 Chevrolet Corvette Stingray — LT1 6.2L
2017–2019 Chevrolet Corvette Grand Sport — LT1 6.2L
2015–2019 Chevrolet Corvette Z06 — LT4 supercharged 6.2L
2016–2024 Chevrolet Camaro SS — LT1 6.2L
2020–2024 Chevrolet Camaro LT1 — LT1 6.2L
2017–2024 Chevrolet Camaro ZL1 — LT4 supercharged 6.2L
2016 and later Cadillac CTS-V models through 2019 — LT4 supercharged 6.2L
2022 and later Cadillac CT5-V Blackwing — LT4 supercharged 6.2L
2023 and later Cadillac Escalade-V — LT4 supercharged 6.2L
Fitment follows the installed engine block, particularly on swapped or previously modified vehicles. Confirm block compatibility before ordering.
Professional Machining Required
These are not drop-in replacement caps. Installation requires a disassembled block and precision machining by a qualified engine machine shop.
The installation must establish the dowel locations, fit the caps, and finish the main bearing tunnel. The builder must then verify:
Main bearing housing bore size and alignment
Main bearing oil clearances
Crankshaft endplay
Rotating-assembly clearance
Fastener engagement and assembly preload
This is an upgrade to plan during a complete engine build or rebuild. It does not repair damaged block structure or eliminate the need for correct machining, lubrication, and tuning.
Katech LT1/LT4 Billet Steel Main Caps #KAT-A6985
Build the foundation before you build the boost.
Forged pistons and rods are only part of a strong bottom end. The main caps help hold the crankshaft’s bearings in position, and maintaining that support becomes increasingly important as cylinder pressure and engine speed rise.
The Katech KAT-A6985 main cap set combines billet steel construction with LS7/LS9-style steel locating dowels for compatible Gen V LT1 and LT4 blocks. Designed for performance engine builds, this upgrade addresses both cap strength and the way the caps locate within the block.
Strength and positive location
Main caps form the lower half of the crankshaft’s main bearing housings. Combustion forces and rotating-assembly inertia load these housings repeatedly during engine operation.
From an engineering standpoint, movement or distortion at this joint can affect bearing housing geometry and the bearing’s operating conditions. The objective is to keep the assembled main bearing tunnel stable, correctly sized, and aligned.
Katech’s design uses two steel locating dowels per cap, rather than relying on the factory block’s aluminum register walls for lateral location. The dowels establish a positive locating interface; the main fasteners provide the clamping load that holds the assembly together.
Suggested ARP main stud upgrade #234-5802
Griffin Motorsports recommends choosing the ARP 234-5802 main stud kit when planning this conversion. ARP specifies 8740 chromoly steel, heat-treated to a 190,000 psi tensile-strength rating, for its main studs. The kit includes main studs, nuts, washers, and side bolts.
Studs remain seated in the block while the nuts are tightened, helping provide more consistent assembly preload and reducing repeated installation wear on the block threads.
Select your final fasteners before machining. Changing fasteners or assembly preload can change main bearing housing dimensions. Final machining must use the same fasteners, lubricant, and specified preload intended for engine assembly. Block machining and align boring/honing required.
Product Specifications
Katech part number: KAT-A6985
Application: Compatible Gen V LT1 and LT4 engine blocks
Cap material: Billet steel
Includes: Five main caps and steel locating dowels
Locating arrangement: Two LS7/LS9-style steel dowels per cap
Optional fastener upgrade: ARP 234-5802 main stud kit
Installation: Block machining and align boring/honing required
Vehicle Applications
2014–2019 Chevrolet Corvette Stingray — LT1 6.2L
2017–2019 Chevrolet Corvette Grand Sport — LT1 6.2L
2015–2019 Chevrolet Corvette Z06 — LT4 supercharged 6.2L
2016–2024 Chevrolet Camaro SS — LT1 6.2L
2020–2024 Chevrolet Camaro LT1 — LT1 6.2L
2017–2024 Chevrolet Camaro ZL1 — LT4 supercharged 6.2L
2016 and later Cadillac CTS-V models through 2019 — LT4 supercharged 6.2L
2022 and later Cadillac CT5-V Blackwing — LT4 supercharged 6.2L
2023 and later Cadillac Escalade-V — LT4 supercharged 6.2L
Fitment follows the installed engine block, particularly on swapped or previously modified vehicles. Confirm block compatibility before ordering.
Professional Machining Required
These are not drop-in replacement caps. Installation requires a disassembled block and precision machining by a qualified engine machine shop.
The installation must establish the dowel locations, fit the caps, and finish the main bearing tunnel. The builder must then verify:
Main bearing housing bore size and alignment
Main bearing oil clearances
Crankshaft endplay
Rotating-assembly clearance
Fastener engagement and assembly preload
This is an upgrade to plan during a complete engine build or rebuild. It does not repair damaged block structure or eliminate the need for correct machining, lubrication, and tuning.
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