Monthly Archives: September 2016

450 Horsepower – 480 LB-FT torque 396 Big Block Chevy

450 Horsepower – 480 Lb-Ft Torque 396 Big Block Chevy

JMac Performance built a 450 Horsepower – 480 LB-FT Torque 396 Big Block Chevy. The goal with this build was a solid street engine that could be a weekend cruiser with enough attitude to perform well at the track.

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The Foundation
Block and Cylinder heads

The build started with a rare factory 4 bolt main 396 block # 3855962.

The block received the usual machine work: magnaflux’d , bore and honed .030 over with a torque plate, decked, and line honed.

I always use ARP main bolts for added strength

You can tell it’s a 396 block by the intake valve reliefs machined into the deck

To help eliminate cracks all the extra casting flash was ground off

 Before

 

 After

The oiling holes were smoothed and lifter valley was cleaned up.

     

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Cylinder heads

Stock # 3872702 cylinder heads with a 98 cc closed combustion chambers were used. They received magnfux’d, decked, new valve guides, 3 angle valve job, and Manley 2.07″ intake and 1.725″ exhaust stainless steel valves.

Because the 396 has a small 4.125″ bore cylinder I resisted the temptation to install larger valves.  I did use a .100″ longer valve to accommodate the taller lift of a bigger camshaft.

The cylinder heads received a pocket porting where the bowl under both valves were opened up, valve guides were narrowed, and the exhaust ports were polished.

In the 60’s gasoline had lead in it, not so much in 2017. To accommodate running on unleaded fuel harden valve seats were also installed.

To ensure no oil gets into the combustion chamber the guides were cut so Viton oil seals could be installed.

The Bottom End

This 396 already had a great factory forged steel crankshaft. It was turned .010 under on both the mains and the rod journals, polished, oil holes were chamfered, and balanced.

Stock size 6.135″ Scat full floating connecting rods with ARP bolts, forged Icon pistons, and Hastings single moly piston rings were used.  Piston to wall clearances were set between .0035″ – .004″.

The pistons have a small dome which creates a total of 9.5/1 compression with the 98 cc combustion chambers.

 

Main and Rod clearances were set to .00275″and .0025″ respectively and the crankshafts end play was set to .005″

 
 

The oil pump is a standard volume, standard pressure Mellings.  Unless you’re planning on running a 7 quart oil pan or larger a hi-volume pump is not recommended. The oil pump received the usual blue printing to ensure the relief valve worked properly and the cover to gears clearance was correct.

Notice the oil pickup is tack welded to the pump to ensure it does not come loose

The pistons were set at .015″ below the deck

The Valve Train

The heart of the valve train is a Comp Cams custom grind billet hydralic roller # 2640-16 Intake .510″ lift 230 @ .050 –  exhaust .520″ lift 236 @ .050 on a 110 lobe center.

Note: because this is a 1966 block the rear camshaft main journal and the rear cam bearing both have a groove machined in them. Using a non-grooved camshaft and rear bearing in the earlier block with result in engine failure!!

Finishing the rest of the valve train are Comp Cams hydraulic retro-fit roller lifters, Comp Cams one piece push rods, and Scorpion 1.7 ratio roller rocker arms

A double roller timing chain with a Torrington bearing a long with a nylon cam button was installed.  Because the block was line honed a .005″ smaller timing chain had to be used.

The cam was set at 2 degrees advanced

 

Induction, fuel system, and ignition

A Quick Fuel 750cfm double pumper carburetor, Weiand duel plan intake manifold, Edlebrock hi volume mechanical fuel pump and a HEI distributor was used.

The HEI distributor was recurved to have 14 degrees of timing at idle and 38 degrees of timing at 3800 RPM

This engine has the performance needed to be successful at the drag strip or auto cross but has the manners to be a great street cruiser

Click on the link below to see and hear it run on the engine stand

JMac 450 Horsepower – 480 Lb-ft Torque 396

 

450 Horsepower – 500 LB-FT Torque Ford 351W (Windsor) 393 Stroker

450 Horsepower – 500 Lb-Ft Torque Ford 351W (393 Stroker)

JMac Performance put together a 450 Horsepower – 500 Lb-Ft torque 9.75/1 Fuel injected 351 Windsor/393 stroker Small Block Ford. The goal with this build was low RPM high Torque that could move a 4000 pound 56′ Mercruiser, run on pump gas, and have the street manners to be a daily driver.

Ford 351W (393 Stroker) “The Foundation”

I started the build with a mid-1980’s non-roller 351 W, 2 bolt main, 1 piece rear main seal block. I chose the non-roller block because some of the newer late 80’s/early 90’s roller blocks can have stress cracks in the valley above the cam bearings. The non-roller 351W blocks can be easlly converter to roller blocks and have proved to be crack free.

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The block recieved the usual hot tank, magniflux, .030 over bore and hone with a torque plate, line hone, and decking.  I also ground off all the extra casting flash and opened up the oil holes in the lifter valley to ensure the oil returns to the oil pan without restriction.

Before – from the factory

 

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After it has been opened up

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Grinding off the excess casting flash makes the engine easier to work on and helps eliminate stress cracks.

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Ford 351W (393 Stroker) “Bottom End”

Over 500 Lb-Ft of torque can put quite a strain on the main caps.  A main cap girdle was used along with ARP main cap bolts to ensure everything stayed tight and in-line.

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Because of the 3.850″ stroke of the crankshaft the main gridle needed to be clearanced. The throw of the crankshaft and the big end of the connecting rods need a minimum of .060 clearance.

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A forged SCAT 3.850″ stroke crankshaft, forged SCAT 6.2″ connecting rods with ARP bolts, forged 4.030″ ICON Pistons, Speed-pro single moly piston rings, and Cleveite bearings were used to complete the bottom end.

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Ford 351W (393 Stroker) “Oiling System”

A mellings high volume oil pump was used to keep the bottom end well lubed. The main gridle needed to be clearanced to ensure a proper fit between it and the oil pump. To keep the integrity of the oil pump it’s better to grind the main gridle not the oil pump.

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From the factory the oil holes that drain from the cylinder heads back to the oil pan can sometimes be mis-aligned. To ensure oil flows freely the holes were opened up and chamfered.

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With all JMac Performance engine builds the oil pump is disassembled to ensure all clearances are correct and to verify the relief valve and  pressure spring work freely.

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Ford 351W (393 Stroker) “Cylinder Heads and Induction System”

AFR Renegade 185 cc heads were used, they are CNC ported and are an exceptional cylinder head. A larger cylinder head would have made more horsepower, However the customer stressed they wanted low RPM torque over higher RPM horsepower. The smaller cylinder heads help increase the intake velocity at lower RPM thus creating a more responsive and higher torque engine.

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Because the customer wanted a maintenance free fuel system with maximum drivability the FAST EZ fuel injection system was used.  It is a self learning, extremely easy system to install and use and no tuning is needed!

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I used an Edelbrock RPM Performer dual plane intake manifold. It matched the operating RPM of the engine very well, from 2500 – 6500 RPM. I have found that most fuel injection systems do not like full dual plane intake manifolds. So, about 1/2″ was removed from the intake manifolds center divider to help both banks equalize better.

Before                                                                                            After

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Ford 351W (393 Stroker) “Valve Train”

As I mentioned earlier a non-roller block was used over the crack prone later roller blocks. A hydraulic roller camshaft and valve train was to be used so I convered the block to a roller type by installing a Comp Cams conversion kit.  It allows the use of less costly non-link bar lifters. A lifter valley “spider” and “wish bone” alignment links are adapted to the block.

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Two small 1/4″-20 holes are drilled and tapped into the lifter valley floor to hold down the lifter “Spider”. The edge of the lifter valley where the lifter wish bones links sit are clearanced to ensure full movement.

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A set of Dura-Bond high performance camshaft bearing were installed.

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A Comp Cams XR264RF-HR10 small base circle camshaft was used. A small base circle camshaft is required to ensure proper oiling to the lifters. If a standard base circle camshaft is used with the non-link bar style roller lifters they extend to far out of the lifter bore thus blocking the oil passages and greatly reduce the oil moving through the system.

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Although it is an non-roller block the roller thrust plate can still be used to keep the camshafts end play in check. Because the block was line honed a -.005 smaller double roller timing chain with a needle bearing thrust washer was used. Notice the flat head allen screws used to hold the thrust plate in place, they are needed to create a flat surface for the timing chain thrust bearing.

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To top of the valve train a set of Trickflow 7.600″ .080″ thick push rods were used along with a set of 1.6 ratio Hardland Sharp full roller rocker arms.

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Ford 351W (393 Stroker) “Test run”

With the engine complete all that was needed is a quick test run on the engine stand to ensure all systems worked properly.  After setting the intial parameters on the FAST EZ fuel system the engine started right up. The timing was set to 14 degrees at idle of 850 RPM and 36 degrees total all in at 3500 RPM.  As the engine ran I could see the air/fuel ratio’s begin to reach their target settings. The engine is ready to install in the 56″ Mercury Mercuriser and after about a tank of fuel will be fine tuned for many years of trouble free driving.

   Click here to see the engine on the run stand

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450 Horsepower – 500 Lb-Ft Torque Ford 351w / 393 stroker engine.

Contact John@JMacPerformance.com if you’d like more details on this engine build.