Engine
Related Helpful Data and Formulas
Cubic Inch Displacement
= Bore x Bore x
Stroke x (.7854 x # cylinders)*
* use the following:
8
cylinder = 6.2832
6
cylinder = 4.7124
4
cylinder = 3.1416
CC in Deck
Clearance
=
Bore x Bore x 12.87 x Deck Clearance
CC in Head Gasket
=
Bore x Bore x 12.87 x Compressed Gasket Thickness
Net Combustion
Chamber Volume = Combustion Chamber Volume – Dome Volume + Deck
Clearance
CC + Gasket CC
True Compression
Ratio
=
(Cubic Inch Displacement x 16.39 / Number of Cylinders / Net
Combustion Chamber Volume) + 1
Bore–Stroke Ratio
=
Bore / Stroke
(Theoretically,
the larger the Bore-Stroke ratio, the higher the engine
will RPM.)
Rod Ratio
=
Length of rod (Center to Center) / Stroke
Common
rod ratio in drag racing is about 1.8, versus circle track 1.7)
Crankshaft Throw
=
Stroke / 2
Stock carburetors have a VE of
85%, Good reworked carbs will have a VE of 98%
Or
Max RPM = Carb size x 3456 / VE/ CID
Horsepower based on ET
HP = Weight / (ET / 5.825)3
Horsepower based on Trap Speed HP = (MPH / 234)3 x Weight
Intake Manifold Surface your intake when you surface
your block or heads.
Intake Manifold
Block or
Heads
Side Bottom
.005
.006 .009
.010
.012 .017
.015
.018 .025
.020
.025 .034
.025
.031 .043
.030
.037 .052
Miles Per Hour
= RPM x Tire Diameter / Final Gear Ratio /
336.31
Or
=
RPM x Tire Rollout / Final Gear Ratio / 1056
To set Chevrolet Valve Lash, When the #1
cylinder valves do not move do not move as the crank approaches
TDC (00), the engine is in the #1 firing position.
Move crank to Zero degrees.
1.
Adjust
Exhaust #8 #4 Intake #7 #2
2. Rotate
Crank 1800 and Adjust Exhaust #3 #6 Intake #1 #8
3. Rotate
Crank 1800 and Adjust Exhaust #5 #7 Intake #4 #3
4. Rotate
Crank 1800 and Adjust Exhaust #2 #1 Intake #6 #5
Common Torque (FT-Lbs.):
Mains 70-80 Rods 50-65 Heads
65 Intake 30
Exhaust 20 Oil Pan 15 Cam
30
Carburetor 10
Damper 70 Flywheel 65 Clutch
30 Water Pump 30
Common Clearances:
Main Bearings
0.002-.0025”
Crank End Play
0.002-.0025”
Top Ring End Gap
Stock 0.010” Race 0.020”
Second Ring End Gap
Stock 0.012” Race
0.015”
Rod Bearings
0.002-.003”
Steel Rod Side Play
0.008-.010”
Aluminum Rod Side Play
0.050-.070”
Deck Clearance Minimum
Stock .008” Race 0.004”
Piston to Wall
0.005-.008”
Piston To Valve
Intake 0.080” Exhaust
0.100”
Oil Pan to Pick up
3/8” No
more or no less!
Always check Manufacturer’s
specifications and with your Machine Shop!
