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QUICK CUBIC INCH DISPLACEMENT CHART
BORE X BORE X STROKE X
.7854 X NUMBER OF CYLINDERS
EXAMPLE: (SBC) 4.030 X
4.030 X 3.750 X .7854
X 8 (CYLINDERS) = 382.66 Cubic Inches - (383 STROKER)
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10 RULES FOR SUCCESSFUL STROKER
BUILDS
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Select as long as a rod as possible to minimize
the frictional losses from side loading and cut the engine's mechanical noise.
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Select the lightest reciprocating components
for the bottom end.
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Use an effective crank damper
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Use an oil pan that keeps the oil away from
the bottom end rotating assembly as entertainment will cost big power and may lead to failure.
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Go for as high a compression ratio as possible
as it will off-set the engine's reduced mechanical efficiency due to it's greater piston friction.
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Use cylinders heads with valves as large
as possible as there are a lot more cubes to feed.
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Be sure to tighten up the cam's lobe centerline
angle (LCA) from whatever was optimum before by about 1 degree for every 16 cubic inches of capacity increase.
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Increase valve lift at least the same proportion
as the increase in displacement.
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Make sure the induction system has enough
flow capability to handle the extra cubic inches.
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Try to keep the induction system cool as
this makes more difference with a stoked engine. | |
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Will nitrous effect engine reliability? |
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It depends. The key is choosing the correct
amount of added horsepower for a given application. As energy increases in the cylinder, so does the load on engine components.
If the load increases exceed the ability of the components to handle them, added wear will occur. A nitrous kit that uses
the correct calibration does not usually cause increased engine wear. Most nitrous kits are designed for use on demand and
only at wide open throttle, meaning that nitrous is only used when you want it, not all the time. |
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What are some general rules for even higher
horsepower gains with nitrous? |
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Generally, forged pistons are one of the best modifications you can make.
Retard ignition timing by 4-8 degrees (1 to 1-1/2 degrees timing retard per 50 horsepower gain). In many cases, a higher flowing
fuel pump may be necessary. Higher octane (100+) racing fuel may be required, as well as spark plugs one to two heat ranges
colder than normal with gaps closed .025"-.030". For gains over 250 horsepower, additional modifications may include a forged
crankshaft, high quality connecting rods, a high output fuel pump dedicated to feeding the additional fuel requirements of
the nitrous system, and racing fuel with high specific gravity and an octane rating of 110 or more. |
How much of a performance improvement can
I expect with a nitrous system? |
For many applications an improvement of
one to three seconds and 10 to 15 mph in the quarter-mile can be expected. |
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What is camshaft lobe separation and how
does it effect the engine? |
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Lobe separation is the distance (in camshaft degrees) that the intake and
exhaust lobe centerlines are spread apart. This separation determines where peak torque will occur within the engine’s
power range. Tight lobe separations (106° or shorter) cause the peak torque to build early in rpm range and peak-out in a
short amount of time. Broader lobe separations, such as 112°, allows the torque to build over a wider rpm range. |
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How does an increase in rocker arm ratio
improve engine performance? |
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The lobe lift of the camshaft is increased by the ratio of the rocker arm
to produce the final amount of valve lift. A cam with a .320” lobe lift using a 1.5 ratio rocker arm will have a .480”
valve lift (.320” x 1.50 = .480”). If you install 1.6 ratio rocker arms, final lift will increase to .512”
(.320” x 1.60 = .512”). The engine will respond as if a slightly larger lift cam had been installed. Increasing
the rocker arm ratio is an easy way to improve the performance of an existing cam. |
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Bolt Torque
Spec Chart for Ford
These specs are for stock-type bolts with light engine oil applied to the threads and
the underside of the bolt head. Moly and other lubes offer reduced friction and increased bolt tension, which will affect
the torque figure. If you use aftermarket performance bolts like ARP's, you should follow the recommended torque specifications. |
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260, 289, 302 |
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Fastener Type |
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Torque Spec |
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Main cap bolts |
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60-70 ft.-lbs. |
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Outer main cap bolts, |
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35-40 ft.-lbs. |
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Connecting rod bolts |
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19-24 ft.-lbs. (40-45 ft.-lbs. for 289 HP Boss 302) |
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Cylinder head bolts |
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65-72 ft.-lbs. |
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Rocker arms |
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17-23 ft.-lbs. |
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Intake manifold bolts |
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23-25 ft.-lbs. |
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Oil pump bolt |
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23-28 ft.-lbs. |
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Cam bolts |
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40-45 ft.-lbs. |
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Cam thrust plate bolts |
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8-10 ft.-lbs. |
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Harmonic damper bolts |
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70-90 ft.-lbs. |
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Flywheel/flexplate bolts |
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75-85 ft.-lbs. |
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Pressure plate bolts |
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35 ft.-lbs. |
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Front cover bolts |
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12-15 ft.-lbs. |
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351W |
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Fastener Type |
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Torque Specs |
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Main cap bolts |
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95-105 ft.-lbs. |
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Connecting rod bolts |
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40-45 ft.-lbs. |
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Cylinder head bolts |
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90-100 ft.-lbs. |
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Rocker arms |
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17-23 ft.-lbs. |
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Intake manifold bolts |
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23-25 ft.-lbs. |
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Oil pump bolt |
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23-28 ft.-lbs. |
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Cam bolts |
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40-45 ft.-lbs. |
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Cam thrust plate bolts |
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8-10 ft.-lbs. |
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Harmonic damper bolt |
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70-90 ft.-lbs. |
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Flywheel/flexplate bolts |
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75-85 ft.-lbs. |
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Pressure plate bolts |
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35 ft.-lbs. |
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Front cover bolts |
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12-15 ft.-lbs. |
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351C, 351M |
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Fastener Type |
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Torque Spec |
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Main cap bolts |
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95-105 ft.-lbs. |
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Connecting rod bolts |
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40-45 ft.-lbs. (45-50 ft.-lbs. for Boss 351C) |
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Cylinder head bolts
(follow factory torque sequence) |
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105 ft.-lbs. (125 ft.-lbs. for Boss 351C) |
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Rocker arms (non-adjustable) |
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18-22 ft.-lbs. |
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5/16 in. intake manifold bolts |
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21-25 ft.-lbs. |
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3/8 in. intake manifold bolts |
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28-33 ft.-lbs. |
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Oil pump bolt |
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25 ft.-lbs. |
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Cam bolts |
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40-45 ft.-lbs. |
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Cam thrust plate bolts |
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9-12 ft.-lbs. |
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Harmonic damper bolt |
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70-90 ft.-lbs. |
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Flywheel/flexplate bolts |
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75-85 ft.-lbs. |
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Pressure plate bolts |
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35 ft.-lbs. |
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Front cover bolts |
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12-18 ft.-lbs. |
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429-460 |
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Fastener Type |
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Torque Spec |
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Maincap bolts |
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95-105 ft.-lbs. |
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Connecting rod bolts |
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40-45 ft.-lbs. |
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Cylinder head bolts |
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140 ft.-lbs. |
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Rocker arms (non-adjustable) |
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18-22 ft.-lbs. |
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Intake manifold bolts |
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25-30 ft.-lbs. |
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Oil pump bolt |
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25 ft.-lbs. |
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Cam bolts |
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40-45 ft.-lbs. |
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Harmonic damper bolt |
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70-90 ft.-lbs. |
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Flywheel/flexplate bolts |
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75-85 ft.-lbs. |
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Pressure plate bolts |
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35 ft.-lbs. |
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Front cover bolts |
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12-18 ft.-lbs. |
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360, 390, 406, 427, 428 FE |
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Fastener Type |
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Torque Spec |
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Main cap bolts |
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95-105 ft.-lbs. |
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Crossbolts for 406 and 427 |
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40 ft.-lbs. |
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Connecting rod bolts |
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40-45 ft.-lbs. (53-58 ft.-lbs. for 406 and 427) |
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Cylinder head bolts |
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80-90 ft.-lbs. (100-110 ft.-lbs. for 1963-67 427) |
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Rocker arm shaft bolts |
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40-45 ft.-lbs. |
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Intake manifold bolts |
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32-35 ft.-lbs. |
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Oil pump bolt |
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12-15 ft.-lbs. |
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Cam bolts |
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40-45 ft.-lbs. |
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Harmonic damper bolt |
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70-90 ft.-lbs. |
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Flywheel/flexplate bolts |
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75-85 ft.-lbs. |
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Pressure plate bolts |
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35 ft.-lbs. |
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Front cover bolts |
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12-15 ft.-lbs. |
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Chevy Torque
Specs
You don't need to do a lot of book work to find torque specs for your Chevy engine, because
we've done it for you! Just print it out and post it in your shop or toolbox.
These specs are for stock-type bolts with light engine oil applied to the threads and
the underside of the bolt head. Other lubes, moly, and aftermarket bolts will have different torque specs. |
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Small Chevy |
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Fastener Type |
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Torque Spec |
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7/16 in. outer main cap bolt |
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65 ft.-lbs. |
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7/16 in. inner main cap bolt |
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70 ft.-lbs. |
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3/8 in. outer main cap bolt |
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40 ft.-lbs. |
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11/32 in. connecting rod bolt |
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38-44 ft.-lbs. |
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3/8 in. connecting rod bolt |
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40-45 ft.-lbs. |
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Cylinder head bolts |
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65 ft.-lbs. |
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Screw-in rocker arm studs |
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50 ft.-lbs. |
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Intake manifold bolts (cast iron heads) |
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30 ft.-lbs. |
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Oil pump bolt |
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60-70 ft.-lbs. |
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Cam sprocket bolts |
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18-20 ft.-lbs. |
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Harmonic damper bolt |
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60 ft.-lbs. |
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Flywheel/flexplate bolts |
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65 ft.-lbs. |
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Pressure plate bolts |
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35 ft.-lbs. |
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Bellhousing bolts |
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25 ft.-lbs. |
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Exhaust manifold bolts |
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25 ft.-lbs. |
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Big Chevy |
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Fastener Type |
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Torque Specs |
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Main cap bolt, 396-427 2-bolt |
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95 ft.-lbs. |
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Main cap bolt, 396-454 4-bolt (inner/outer) |
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110 ft.-lbs. |
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3/8 in. connecting rod bolt |
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50 ft.-lbs. |
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7/16 in. connecting rod bolt |
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67-73 ft.-lbs. |
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Cylinder head bolts, long |
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75 ft.-lbs. |
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Cylinder head bolts, short |
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65-68 ft.-lbs. |
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Screw-in rocker arm studs |
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50 ft.-lbs. |
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Intake manifold bolts (cast iron head) |
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25 ft.-lbs. |
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Oil pump bolt |
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65 ft.-lbs. |
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Cam sprocket bolts |
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20 ft.-lbs. |
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Harmonic damper bolt |
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85 ft.-lbs. |
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Flywheel/flexplate bolts |
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60 ft.-lbs. |
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Pressure plate bolts |
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35 ft.-lbs. |
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Bellhousing bolts |
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25 ft.-lbs. |
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Exhaust manifold bolts |
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20 ft.-lbs. |
Carb Formula
The first thing to consider here is the cfm that you will need
for your engine. There's a simple formula available that will put you right in the cfm ball park. The formula for naturally
aspirated gasoline engines is:
Engine Size (c.i.d.) X Maximum rpm/3,456=cfm@100
percent Volumetric Efficiency (VE)
Example: 350 c.i.d. X 6,000 rpm=2,100,000/3,456=608
cfm
Approximately 608 cfm would be required for this engine. However, most street
engines are capable of achieving only about 80 percent VE; a modified street engine with ported heads, headers, good intake,
and carburetor can achieve about 85 percent VE; a fully modified race engine can achieve 95 percent or greater VE. The cfm
number arrived at with this formula must be factored by this percentage.
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