Reply to "DeTom on retarded cams, adding lightness and finding the right wrench"

DeTom, here's a reasonable engine build using factory parts as much as possible. This criteria establishes a foundation that you can build upon to make anything from a durable hot street motor to a serious race motor. The budget needed to accomplish this work is the minimum budget I recommend spending in order to have the peace of mind that a thorough job of preparation has been performed.
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Short Block

Stock Displacement, 351 to 357 cubic inches

(1) OEM block
(A) Align honing if needed
(B) Cylinder boring if needed (avoid going more than 0.030” over). If the cylinders are bored they should be "indexed" to the crankshaft centerline during the boring process.
(C) Cylinder honing as per the ring manufacturer's spec, with head plates and main caps torqued in place.
(D) Decks milled the minimum amount that levels them front to back and equalizes their height side to side. Clevelands are normally decked 0.012" to 0.015" (nominal) but please avoid decking them any more than that. If they are decked more than that it becomes difficult to achieve the compression ratio goal for a street engine.

(2) OEM crankshaft. If the journals of a nodular iron crankshaft are ground undersize the journals MUST be polished afterwards. Polishing & tuftriding are a good idea anyway to better lubricate the journals and to better cope with the heavy duty bearings which have less "imbed-abilty" than standard bearings.

When a machinist hones the main bearing saddles in the block or grinds the crankshafts journals its imperative to double check the work for taper and concentricity with gauges capable of measuring 0.0001".

(3) OEM rods
(A) Install ARP bolts & nuts
(B) Resize the big end

(4) Forged Flat Top pistons TRW (L2379F) or Ross (full round skirts). The round skirts of the Ross pistons spread thrust loads and greatly help to prevent cylinder wall cracking, they are the better choice. They are also designed for thinner rings and wrist pin oiling.

(5) Lightweight steel flywheel (~30 pounds or less)

(6) New crank dampener, a nice fat one (i.e. heavy) like the Boss 351 damper. Steel hub & steel ring, fully bonded. An ATI damper or a BHJ Dynamics damper are both really good choices. The Romac damper is not fully bonded but it is a good damper and a bit less expensive.

(7) Dynamic balance the reciprocating assembly (not the same as internal balancing)

(8) New top quality, hand fitted rings (Hastings, Total Seal, Speed Pro)

(9) Clevite 77 main & rod bearings

>The 351C does not have a defective cooling system. Its cooling system was advanced for its day, and it requires a specific high-flow thermostat to operate properly. That thermostat was unusual for its day, it was not designed the same as the thermostat used in any other American V8. That’s where the problem lies, as most parts counters supply a Windsor thermostat to 351C customers, which is the wrong thermostat.

(10) A Robertshaw 333-180 thermostat (Summit #BRA-333-180) is the correct OEM thermostat. Install no other thermostat in your 351C.

(11) Flow Kooler coolant pump increases flow at low rpm, a good idea for a Pantera. Stewart Components stage 4 351W racing coolant pump can be modified to fit the 351C and offers 4 times higher flow capacity (its rated to flow 160 gpm!).

(12) Rubber rear crankshaft seal (OEM seal was made of rope). Remove the small pointed pin in the seal groove of the #5 main bearing cap.
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Cleveland Lubrication 101

(1) Install Moroso #22050 oil restrictor kit for all 5 cam bearings (0.060”) this requires two kits to achieve enough small restrictors. Do not use the larger restrictor in the left side lifter oil passage. The restrictor for cam bearing #1 requires "special" installation. It is not installed in the same manner as the other 4, if it were it would limit oil to the #1 main bearing. It must be installed deeper within the oil passage.

(2) Install a new standard volume oil pump, Melling #M84A, NAPA #601-1024. The standard 351C oil pump is actually a high volume oil pump, it has a taller rotor than the oil pumps in other Ford V8s. However, if you're not going to install tappet bore bushings a high volume pump "may" improve crank bearing lubrication. I wrote "may" because many lubrication system modifications are fuzzy and theoretical, whereas installing the tappet bore bushings is a "sure" thing.

(3) Fully grooved main bearings (requires using the upper shells from two bearing sets).

(4) Set the bearing clearances properly. Approximately 0.001" clearance per inch of journal diameter. Its usual to run the mains a bit "tight" and the rods a bit "loose" in a 351C.

(5) If you're just going to cruise, never drive your car fast, you can make-do using the factory oil pan. If you are using the factory oil pan, use one with a built-in windage tray, or install an aftermarket windage tray. Cars that are driven fast in corners, accelerated fast, and stopped fast really need a high capacity racing pan with baffles, hinged doors, a windage tray and a scraper. It should be designed to fit in the specific chassis where the motor will be installed & for the intended usage of the vehicle. Pantera oil pan: Armando #404 or Aviaid #155-55365.

(6) Use the high volume oil pump pick-up with the factory oil pan. It was standard equipment in the Boss 351 & 351 Cobra Jet versions. Or use the pick-up provided with the high capacity oil pan.

(7) Install tappet bore bushings to control oil flow to the valve train and improve bearing lubrication. If tappet bore bushings are not installed oil flow to the valve train must be controlled either via oil restricting solid flat tappets, or via push rods with 0.040" restrictors in one tip for hydraulic valve train. Solid roller tappets must use the bushings.

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Heads

(1) Select either 1970 (D0AE) or 1971 (D1AE) closed chamber 4V heads. The D0AE heads are best with stock pin height pistons (like the TRW flat tops) and an un-decked block, or for building more dynamic compression with a cam that closes the intake valve later than 70 degrees ABDC. The D1AE head is best with an increased pin height piston (like the Ross pistons) and/or a decked block. The goal for an engine operating on 91 octane pump gas is about 7.6:1 or 7.7:1 dynamic compression.

(2) One piece, single groove, stainless steel valves: Manley Race Master intake and Severe Duty exhaust. Do not use the OEM valves as they have a reputation for dropping the valve heads while the motor is running.

(3) Bronze valve guides

(4) Repair of any recessed valves

(5) Valve springs with about 120 pounds seated force, 330 pounds over the nose (for flat tappet camshafts). Use steel spring cups, titanium spring keepers for the intake valves, chromoly spring keepers for the exhaust valves.

(6) Factory rocker arms & steel fulcrums (4V fulcrums) are OK for hydraulic cams up to about 0.550" net lift. Stronger (ARP) fasteners for the fulcrums are good insurance against "bolt-stretch" because the fulcrum bolts are only 5/16". If you need a better rocker arm, or adjustable valve train consider machining the rocker pedestals and using Yella Terra YT6321 rocker arms. I like the T&D Machine rockers, but they're even more expensive than the Yella Terra rockers. I don't personally use or recommend push-rod guided rocker arms.

(7) Typical Cleveland port work is recommended but not mandatory: this includes bowl clean-up, multi-angle valve seat profiling, exhaust port porting & a bit of valve unshrouding in the combustion chamber. Obviously the more power you expect to make, the more porting such as this will help you achieve your goal.
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Camshaft

(1) Three choices:
(A) Select a Cobra jet camshaft; specs are 270/290 duration, 0.481"/0.490" lift. Set it at 117 degree intake centerline (factory cam) or 115 degree intake centerline (aftermarket replacement).
(B) Ford offered a hotter flat tappet hydraulic camshaft #D1ZZ-6250-BX which was basically a hydraulic tappet version of the Boss 351 cam. It was once a very popular cam, it is available today from a few aftermarket suppliers such as Melling (#24224). The cam specs are 290/290 advertised duration (219/219 @ 0.050), 0.505”/0.505” lift, 114 degree LSA. This cam has 62 degrees overlap, which is about as much overlap as you ever want for a street engine; FYI the 351 Boss camshaft had 58 degrees overlap.
(C) Have a cam custom ground to this spec: 276/286 advertised duration, 112 degree intake centerline, 117 degree exhaust centerline. 52 degrees overlap, exhaust valve opens at 80 degrees BBDC, intake valve closes at 70 degrees ABDC. Net valve lift in the range of 0.550" to 0.600" depending upon the lobes chosen.

(2) Speed Pro HT900 hydraulic flat tappets.

(3) Seamless chrome moly tubing push rods. 3/8 diameter 0.080” wall, or 5/16” diameter 0.116" - 0.120" wall.

(4) Steel timing chain set, 9 keyway crank sprocket. Such as Roll Master #CS3091

(5) Be sure to use motor oil with excellent anti-wear properties, such as Valvoline VR1 10W30 or 20W50
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Ignition

(1) Rebuilt & recurved Duraspark distributor (sourced from a 1977 – 1982 351M, 400 or 460). The MSD distributor with vacuum advance is a good substitute, it uses the same magnetic pick-up as the Ford distributor.

(2) Duraspark I module (sourced from a 1977 – 1979 California vehicle with a 302 V8)

(3) Duraspark I coil. No substitutes.

(4) Duraspark II wiring harness: Painless Wiring #30812, requires a bit of modifying for the Duraspark I module & coil.

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Fuel System

(1) Blue Thunder dual plane intake manifold. This manifold was originally designed by Ford engineers.

(2) Holley style 750 CFM carburetor with annular booster venturis. Plus street-performance calibration and electric choke. I recommend vacuum secondaries, but some guys will prefer mechanical secondaries (double pumper carbs).

(3) Robb Mc Performance #1020 mechanical fuel pump (good for up to 550 BHP). Groovy part, groovy company. "Fat" oil filters hit the fuel pump.

(4) Panteras need to increase the size of the tubing supplying the fuel pump.
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Exhaust

(1) 4V Headers (1-7/8” to 2” primaries)

(2) Low restriction tail pipes (2-1/4" through 2-1/2") and mufflers.

Pantera exhaust: Don't use the OEM Ford Spec exhaust, the European GTS exhaust is a good recommendation. A cam which opens the exhaust valve early helps the engine cope with the small ANSA mufflers.
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From a Strong Performer to a Wild Child

This engine will run forever in this state of tune. It has a mild burble at idle, like any muscle car era factory performance motor did. It has lots of vacuum at idle, peak BHP will be about 365 at 5800 RPM with the Cobra Jet cam, 20 more with the 290/290 hydraulic cam. It has a very enjoyable, street friendly, wide, power band. The limiting factor to this motor's power is the relatively low lift camshaft. Substitute a higher lift (low overlap, wide LSA) custom ground cam and power over 400 bhp is easily attainable with good drivability. This is more than ample power to go fast and push the limits of traction with street tires.

Substitute a solid tappet cam, and matching tappets and valve springs. Increase the size of the carburetor to an 850 Holley; and install a hotter exhaust system and this same build shall make 500 BHP on pump gas. The Holley Strip Dominator intake manifold will return better numbers at peak horsepower and at high rpm, but I don't recommend it for a street engine, and I would personally prefer the mid-range of the dual plane manifold even for circuit racing. With a set-up like this pushing the motor to operate at higher RPM, the 351C turns into a wild child. Better connecting rods are usually part of an engine in this state of tune.
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“A Man’s Gotta Know His Limitations” … Dirty Harry

Enthusiasts competing in drag racing with the 351C get away with making over 600 horsepower without failure of the OEM block or crankshaft; enthusiasts competing in circle track and road course racing with the 351C are not as fortunate however, for that type of competition I recommend setting 500 horsepower & 7000 rpm as your limit if you plan to use OEM block and/or OEM crankshaft. If you want to make more than 500 horsepower I suggest using an aftermarket block with thick cylinder walls and thick bulk heads, an internally balanced and fully counter-weighted steel crank, and better connecting rods.