The Ford V-8 Engine Workshop
The block is essentially the next generation of
289 HP hardware,
but features a forged steel crankshaft, 4-bolt main caps,
and screw-in freeze plugs.
These modifications were developed as part of the 302 Tunnel Port design.
Street versions used connecting rods similar
to the 289 HP while the Trans Am version used heavier 7/16" bolts.
The real magic of the Boss engines
comes from the canted-valve Cleveland cylinder heads. While the Boss 302
is normally considered a 302 with Cleveland heads,
these canted-valve heads were used first on the Boss before
the rest of the Cleveland was developed.
As fitted to the Boss, the heads feature steel spring seats,
screw-in rocker studs, pushrod guide plates, and adjustable
The Boss 302 and 351C-4V head casting are the same except for a minor difference
in water passages. Camshafts were quite similar to the 289 HP.
Due to the larger Cleveland-style heads, the Boss 302 weighs somewhat more
than the normal 302, tipping the scales at 500 lbs.
The street version was conservatively rated at 290 HP @ 5800 RPM. During the '69 Trans Am season the racing engines were producing 470 bhp with a 9,000 rpm redline.
Designed for the road racing environment, the engines featured a scraper style windage
tray. This tray attached to four special main cap bolts with small threaded holes in their heads.