> Does anybody have any experience with an aluminum 351 small block?
I have a Fontana block going together "real soon now".
> What would be the weight difference?
The Fontana block weighs in at 116 pounds versus 172 pounds for a standard
bore 2-bolt main 351C block (as measured by me on a bathroom scale). Iron
9.2" or 9.5" deck SBF race blocks come in at around 205 lbs (per the Ford
Motorsport catalog). With aluminum heads, waterpump, flywheel, and a
mini-starter, it is possible to get the engine weight down to 404 lbs
or so versus 550 lbs for an all-iron 351C.
> Will it last?
I don't see why not. There are plenty of aluminum block engines out
there these days. Take care not to overheat the engine, run the right
coolant, and proper bearing clearances and it should last a good long
time. Also, should something catastrophic go wrong, aluminum can be
welded much more easily than cast iron.
One guy I know did have problems with his because a machine shop attempted
to align-hone the main bores instead of align-boring. This ovaled the
mains as the hone removed more material from the aluminum block than from
the iron main caps. With a rigid cutter, align-boring cuts equally from
both. The same guy also noted that dowel pin location was off on his block
(or was it the cover?)
> Virtually all aluminum "small blocks" are 'Cle-vors' built by Joe Fontana
> in CA.
Joe now has competition from Ford Motorsports who list various aluminum
SBF blocks in their catalog. Those blocks are from RDI (Raceparts
Distribution). Beware that many of these blocks are dry-sump or external
wet sump only. I expect Dart may also be in the aluminum Ford block
business in the near future.
> There is a custom nose piece vaguely reminiscent of a 351-W that houses
> a water pump & the timing chain. A stock Ford Windsor nose piece will
> not fit.
Correct. Fontana supplies the front cover in a standard version or one
modified for sprint car use. The waterpump is from a 351W as well.
> The name Cle-Vor indicates a combination of Cleveland & Windsor design
> features- Cleveland 2.75" crank main bearings and Windsor oiling etc.
> Some but not all stock parts will fit.
Yes, the Fontana is a hybrid of Cleveland and Windsor design features.
The RDI and Dart blocks are closer to Windsor than Cleveland but do have
Cleveland mains and are available in Cleveland deck heights. Either Windsor
or Cleveland heads can be used with the proper intake manifolds and pistons
with the corresponding valve notches.
Here's what I think I know so far about the Fontana aluminum block:
- Available in 9.2" (Cleveland) or 9.5" (Windsor) deck heights.
Mine is a 9.2" deck block.
- Siamesed bore (dry wall, ductile iron top hat cylinder liners, interlock
with flats on sides between bores). Absolute maximum bore is 4.155",
though 4.125" is probably more likely (sonic test to be sure).
- For large diameter bores, recommended headgaskets are Fel-Pro 1022
(left hand) and 1023 (right hand). These gaskets have 4.160" bores,
are notched (one has 2 notches, the other 3 notches) and come with
instructions. Use Fel-Pro 1021 for bores up to 4.1".
- Clearanced for standard full size starter (I'm using a mini starter)
- Compatible with solid or hydraulic flat tappet lifters and solid roller
lifters but does not have the tall bosses for OEM hydraulic roller
lifters (could use the retro-fit reduced base circle stuff)
- 4 bolt main caps on all 5 mains, splayed on 2, 3, and 4.
- Windsor rear intake manifold seal rail shape (requires SVO or Edelbrock
dual end seal style intake). IR EFI intakes are available.
- Windsor oil system layout
- 2.750" main diameter (for Cleveland diameter crank), though I think
Fontana will bore to 3" Windsor mains if requested.
- 351 Cleveland main bearings
- 351 Cleveland oil pan and gasket
- 351 Cleveland oil pump and pick up
- 351 Cleveland cam (13726548 firing order)
- 351 Cleveland cam bearings
- 351 Windsor distributor with Cleveland gear
- 351 Windsor timing chain
- 351 Windsor timing cover gasket
- 351 Windsor water pump ('70-up)
- 351 Windsor end seals (intake end rails)
- Machined to accept M-6701-A351 two-piece rear main seal.
- Pressure port drilled at back of block just above bellhousing flange
(lowest pressure point)
- Fontana recommends using M-6799-A302 oil restrictor kit, even though
Windsor-based oil system (probably just for racing).
- Small block Ford lifters (same for Cleveland or Windsor)
- Small block Ford motor mounts (same for Cleveland or Windsor)
- Fontana specific front cover (included), optional sprint car front cover.
- Custom length pushrods
- Screw-in, O-ringed, Allen head core plugs
- Studs/bolts for block and head combo (available from ARP or Fontana)
- Can be plugged at oil filter or oil pump base for dry sump (remove
for wet sump).
- Has wet sump provision but is currently plugged for dry sump (need to
remove one plug).
- Has pad for internal oil pump (not just external wet sump).
- Ford Motorsport Cleveland-style canted valve aluminum high port cylinder
heads (A3/B351/C302/Yates) require water passages be plugged like a
Windsor block (per SVO cylinder head instruction sheet).
- Windsor cooling system (Windsor thermostat in manifold or remote
thermostat, not Cleveland in-block thermostat).
- Drilled for hydraulic of solid lifters. Can use hydraulic flat, solid
flat, or solid roller. Lifter bosses not tall enough for OEM hydraulic
roller (could use reduced base circle retro-fits).
- Lifter bore angles are non-stock
- Bare block weight = 116 lbs
- Per Super Ford magazine article on Pantera engine, assembled engine weight
is 404 lbs (Fontana block, high port heads, Ford Motorsport intake).
- Gasket deck is 0.900" thick and head stud holes are 2.5" deep (9.5 deck?)
- All core and oil galley holes are threaded for pipe plugs
- Each cylinder is fitted with a 4.270" O.D. dry wall iron sleeve providing
for a maximum bore of 4.155".
- Numbers one and five main caps reatined by two 0.500" studs and two
0.375" studs. The three center caps are held in place with two 0.500"
hardened studs and two splayed 0.375" Allen head cap screws.
- 356-T6 aluminum
- Distance between camshaft and crank centerline is 4.07", same as a 351W.
- Custom front cover is needed because Fontana uses a Cleveland oil pan.
- Coolant flow path is same as a 351W (no return passages in upper front
corners of block like a Cleveland).
Torque specs:
Head studs 115 ft-lbs
Main Studs 1/2" diameter 100 ft-lbs
Main Studs 3/8" diameter 35 ft-lbs
Main Studs 7/16" diameter 55 ft-lbs
Run head studs into block with 10 ft-lbs maximum. Apply light coat
of silicone RTV on N.C. thread of head stud. Re-torque head studs
after initial running. Engine should be at room temperature for
re-torquing.
Instructions to Restrict Oil to Lifter Galleys on Fontana Clevor block
(see illustration of rear of block):
1. Tap 7/16"-14 through rear lifter galley openings. Stop before threads
reach lifter bore or when nose of tap appears.
2. Clean block and install set screws, 5/16" long, 0.073" hole, and use
Loctite.
Basic Instructions for Cleavor Block (already performed on my block):
1. Deburr and polish interior surfaces of block
2. Bore sleeves to size
3. Hone to final size
automatic hone - use Sunnen JHU625
hand operated - use Sunnen AN501
finish should be 14 to 23 RMS
4. Match up water coolant passage holes in block to holes in head gasket
by hand grinding block.
5. Install torque plate to seat sleeves
6. Deck block.
General Notes:
Joe Fontana recommends the main bearing clearances be 0.0015" to 0.0020"
cold (will grow a 1/2 thousandths hot).
Roush pins the cam bearings from the top on his race motors so the cam
bearings do not walk fore-and-aft (material is relatively thin there so
be careful). Roush also helicoils the mains.
Aluminum expands more than iron. The aluminum block and heads can expand
by more than 20 thousandths when hot. Note that this is more than the
lash on a "tight lash" solid lifter cam (required lash of 16 thou is less
than the expansion). You need to set the lash hot.
Miscellaneous Notes (Pantera-specific):
351W waterpump on Fontana front cover will position the pulley in the
same spot as Cleveland and has water outlet on same side but new accessory
brackets will be needed (Windsor type to match the front cover). Will need
to custom fabricate a thermostat housing to coolant pressure tank pipe.
I bleive Marino Perna at PAnteras East has the bits for this.
Hope this helps,
Dan Jones
