Dart 31253654 – Cast Iron GEN VII8.1 Engine Block Chevy Big Block 10.236 Deck, 4.600 Bore
The Gen 7 8.1/8.8 liter big block was used in numerous marine and truck applications. Up until now, there have been very limited options for upgrading its performance potential.
Dart’s new Gen VII block is available with full water jackets including between the cylinder bores, or with siamesed bores to enable larger displacements. The water block is available with a 4.350” bore diameter, and the siamesed bore blocks can be bored to 4.625” diameter.
Standard 10.236” deck height.
• 4.250” and 4.350” bore water blocks.
• 4.250”- 4.625” bore sizes for siamese blocks.
• Provision for factory crank sensor.
• Uses Gen VI timing cover and oil pan.
• Blind head bolt holes.
• Lifter valley bosses for OE style roller lifters and retainer.
• Clutch linkage mounts, side and front motor mounts simplify installation in any chassis.
Material: Superior Iron Alloy
Bore: 4.250″ through 4.600
Bore & stroke: 4.625″ x 4.750″ (Max Recommended)
Cam bearing bore ID: 2.120″ Std
Cam bearings: Coated, Grooved, w/3 oil holes PN# 32210030
Cam bearing O.S. +.010″, +.020″, +.030″
Cam bearing press: .002″
Camshaft position: Standard
Cam Drive: Timing chain, Gear drive & Belt drive
Cam Plug: Standard BBC 2.215″ diameter
Cubic Inch: 638 Max recommended
Cylinder Wall Thickness: .300″ Min @ 4.625″ bore
Deck Height: 10.232″ (259.89mm)
Deck Thickness: Adequate for all applications
Dist. Tap Hole Valley: Yes
Fuel Pump Boss: None
Fuel Pump Pushrod: None
Freeze Plugs: Std. Press in cup plugs 1 5/8″
Head Bolt Pattern: Std GM
Inside Head Studs: None
Lifter Bores:.8427″ – .8437″ Machined for Gen 7 8.1L GM Hyd Roller
Main bearing size: Std BBC
Main bearing bore: 2.937″ – 2.938″
Main caps: Ductil iron, 4 bolt
Oil system: Wet or dry sump – Main priority oiling
Oil Galley, main: 9/16″-1/2″-7/16″
Oil Cooler Holes:None, Can use aftermarket inline
Oil Galley, filter main: 5/8″
Oil Filter: Stock oil filter location
Oil Pan:8.1L Metric bolt patterned oil pan
Rear Main Seal1 piece, No gasket groove Felpro 2920
Hyd. Roller Provisions: Yes
Serial No. On Main Caps, Front passenger side below deck
Starter: Mounts in standard location
Stud & bolt holes: Blind Tapped
Tapped Holes: Metric thread & Pitch
Timing chain / gears: Std BBC GEN VI/GM 8.1L
Timing Cover: GEN VI stock 6 bolt cover or GM 8.1L
Torque Specs: All 1/2″ – 105lbs
Weight: 4.250″ bore (295lbs)
4.350″ bore (280lbs)