This is the Axial .28 Spec 1s 8-Port Racing Engine with Pull-Start and the SG (pilot) Crankshaft.  This has the grey head.  This engine is a direct replacement engine for any .21+ big block engine.  These are awesome engines, and you will have a hard time beating them a this price.  The Axial .28 is a direct fit for all of the Savage trucks, the Losi LST, LST2, Aftershock, as well as the MGT, and most 1/8 scale off-road trucks and buggies.  This engine accepts the HPI Roto-Start shaft starting system made for the K4.6 big block.

High-performance for your 1/8 scale off-road truck or buggy!

Features:

• ABC cylinder construction (Aluminum Bronze and Chrome)
• Composite bodied 8.5mm 3-needle Slide Valve Carburetor, factory reset line on High-Speed Needle and flush needles make resetting to factory specs easy
• SG (pilot) crankshaft with long duration intake
• Eight-port cylinder sleeve
• High volume transfer port design
• Removable button type combustion chamber
• Roto-starter available optionally

Includes:
Axial .28 Spec 1s Racing Engine with Grey Cylinder Head with pull-starter
One Instruction Sheet
One 8.5mm Restrictor
One 8.0mm Restrictor

Requires:
Glow Plug: Cold Heat Range
Fuel: 20-30% Nitro with at least 18% Oil Content
Manifold and Tuned Pipe (Depends on Vehicle)

Specifications:
Displacement: .28 cu in (4.6cc)
Maximum RPM: 36,000
Bore: 18.6mm
Stroke: 16.9mm
Weight: 455g (16.05oz)
Distance Between Mounting Holes Same Side: 20.30mm (0.799")
Distance Between Mounting Holes Opposite Side: 37.03mm (1.45")
Height Bottom of Mounting Tabs/Top of Cylinder Head: 97.27mm (3.83")
Width of Mounting Tabs: 44.92mm (1.76")
Distance from Pull Starter to Front Bearing: 83.22mm (3.276")
Distance from Center of Engine to Front Bearing: 41.61mm (1.63")
Distance from Center of Engine to Pull Starter:  41.61mm (1.63")