Engine Blocks

In the world of racing and performance, BIGGER is always better. Ford Racing gets it - and thats why it offers BOSS small blocks in Big Bore versions. The Ford Racing BOSS blocks are designed to be a replacement for the legendary BOSS 302 and BOSS 351 blocks using the latest technology and manufacturing techniques available. Cast from diesel grade iron with siamese bores, thick cylinder walls and decks, BOSS block strength is far superior to any Ford production block ever offered.

Ford Racing Big Bore 351 blocks make it simpler and more economical to build really BIG small blocks. To insure the most precise bore location, concentricity and integrity, the BOSS Big Bore blocks are machined an additional .125 during the initial block fixturing and boring stage. With an unfinished bore size of 4.120, Ford Racing BOSS 351 Big Bore blocks make really BIG small blocks - as big as 460 cubic inches!

The Ford Racing BOSS block capability has been proven around the world both on the track and on the street. And, all Ford Racing BOSS blocks are cast and machined to the highest industry standards in the USA.

Same as M-6010-BOSS35195 except allows for bigger bore by deleting coolant crossover holes between cylinders
Finished at 4.120" rough bore. Designed for minimum bore wall thickness .180" @ 4.125" (Sonic check recommended for bores greater than 4.125")
9.5" deck height, finished at 9.500" plus .010" to .015"
Maximum recommended stroke 4.250", clearance dependent on crankshaft/connecting rod manufacturer
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
NASCAR inspired front oil feed on both lifter galleys
Revised cooling system passageways
Increased bulkhead material
Threaded core and galley plugs (straight thread port plugs with O-ring)
Requires special length 1/2" head bolts M-6065-BOSS or head studs M-6014-BOSS recommended with M-6049-X306/307/Z304DA heads
Designed for M-6049-X306//X307/C3/D3/Z304DA cylinder heads. Not designed for production 302/351W or M-6049-Y302/Y303/X302/X303/X304/X305 cylinder heads
Uses common OD cam bearings M-6261-J351/R351
Unique cam plug M-6026-S351 included
Designed to be compatible with the original 302 and 351W blocks and includes the following features:
Designed to use stock type timing cover, timing Cover M-6059-D351 recommended (includes fuel pump provision)
Fits factory Mustang oil pan with custom oil pick-up tube M-6622-BOSS302
M-6026-A Service Replacement Plug and Dowel Kit available separately includes O-ring threaded plugs, black anodized aluminum plugs with Buna "O" rings for the oil galleys, water drains and core holes, and dowels for front cover, clutch housing and cylinder heads
Retains clutch cross shaft pivot hole
Original Style oil filter location
Original motor mount boss locations
Original bell housing pattern
Weighs approximately 197 lbs.
Great price and value
The foundation for big bore 9.5" deck projects