Ford Performance Cylinder Block Boss 351 9.5" Deck
Highlights
- Boss 351 Block
- 9.5" Heck Height
- 4.125" Bore Capacity
- 2 and 4 Bolt Main Caps
Ford Performance Boss 351 Cylinder Block with a 9.5" Deck for Ford Mustangs.
The next step in small block performance is here. Start your Windsor build with the Boss 351 Block (M-6010-BOSS35195) from Ford Performance! With reinforced block design, provisions for a roller valvetrain, and four-bolt main caps, this is the foundation for your ultimate tall-deck small block Ford.
Features and Benefits:
- Unmatched Durability
- Ford Performance Quality
- Tall 9.5" Deck Design
- 4-Bolt Main Caps
These blocks take advantage of the latest racing and production-based technologies. Ford Performance manufactures the Boss 351 block using Diesel grade iron, and reinforces critical areas for unmatched durability. They've been tested and proven in motorsport, and are the block that the engineers at Ford Performance choose for their crate engines.
Specifications:
- 4.125" bore capacity (sonic check recommended), finished at 3.990" to 3.995" rough bore
- 9.5" deck height, finished at 9.500" plus .010" to .015"
- Maximum recommended stroke 4.250", clearance depends on crankshaft/connecting rod mfgr.
- Splayed 4-bolt main on 2, 3, 4, main caps
- 2-bolt main on 1 and 5 main caps
- Main bearing bores finished to low limit
- 2.749" main journal diameter (stock 351C size)
- Finished lifter bores
- Machined to accept factory roller lifter guides and lifter guide retainer
- Revised oiling and cooling system passageways
- Siamese bore with drilled coolant crossover
- Increased bulkhead material
- Threaded core and galley plugs (straight thread port plugs with O-ring)
- Requires special length 1/2" head bolts (M6065BOSS) or head studs (M6014BOSS)
- Designed for M6049X306/X307/C3/D3/Z304DA cylinder heads
- Recommended with M6049X306/307/Z304DA heads
- Uses common OD cam bearings M6261J351/R351
- Unique cam plug M6026S351 included
- M6051S331 or M6051CP331 head gasket recommended
- Weighs approximately 205 lbs.
Tech Tip: This is the same block as M6010BOSS35192, except it has a 9.5" deck.
Please Note: Not designed for production 302/351W or M6049Y302/Y303/X302/X303/X304/X305 cylinder heads.
California Residents: Proposition 65 Warning
Related Categories: Mustang Parts, Mustang Engine, Mustang Crate Engines & Cylinder Blocks, Restomod Parts, Restomod Engine
Only for use on pre-pollution controlled vehicles: This product can be used on vehicles that were manufactured before emissions control regulations were imposed. Pre-pollution vehicles are defined as:
- 1965 and older U.S. manufactured California certified vehicles
- 1967 and older U.S. manufactured federally certified vehicles
Installation Difficulty

Advanced skill is required for this installation.