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Inline Cylinder Head Flow

Inline Cylinder Head Flow
Here are 3 flow tests, first on stock head with 1.72 intakes, second on bolt boss removed with 1.84 intake valve, third is same port with a bolt in HI-FLOW lump added.

stock head 1.72 intake

.050" lift 27.3 cfm
.100" lift 52 cfm
.200" lift 103 cfm
.300" lift 149.5 cfm
.400" lift 164.6 cfm
.500" lift 168.5 cfm

This is a head with 1.84 intake valves . It has had valve unshrouding done to it and the guides have been coned shaped.

First port is a intake that has had the bolt boss removed and has a cap screw sitting in the bottom, like it would be in use.
1.84 intake @28" on a superflow
lift flow
open port no lump 
.100 62.1cfm 
.200 115.3cfm  
.300 168.7cfm  
.400 184.3cfm  
.500 195.6cfm 
.600 202.0 cfm


same port with bolt in lump
 .100 lift  59.3 cfm
.200 lift  112.9 cfm
.300 lift   166.9 cfm
.400 lift  203.9 cfm
.500 lift  215.6 cfm
.600 lift  226 cfm

Engine planning

Head flow #'s are in!

Bolt in lumps work! Even with what some people say are small valves, these heads flow very well. Flow tested at a reputable performance shop. This head shows excellent flow at midlift and full lift values. The I/E ratio is 72% which is also nice to have in a naturally aspirated engine.

Picture
What does this airflow do?

So you want to really know what all this AIRFLOW does for your engine. Look at the chart to the right. The graghs are made up of real dyno runs made on a single 292 engine.

The Bolt in Lump Kit is equal change in power as a cam change. When combined with a cam change, gains of over 100 hp can easily be achieved with a mild cam.

To compare the blue lines(stock head) to the green lines (lump port head.

Stock head was 1.72/1.5 valves , no porting.

Lump port head was , 1.94/1.6 valves, ported and lumped.

Same cam was used on both runs. See the tq increase at low RPM? See how the HP was much higher and over a longer RPM?

The other graghs represent the same thing with a performance camshaft on the same 292 shortblock.

The 292 shortblock used had Our 18CC pistons and a balanced lower end. Compression was approximately 9.25 . Intake was a Offenhauser with Holly carb. Exhaust was long tube headers.


 

  • Home
  • Store
    • Valve Covers
    • Side Covers
    • Performance Cylinder heads and Parts
    • Exhaust
    • Accessories
    • Alternator and Power Steering
    • NOS GM Inline 6 and V8 Parts
    • Turbo Related
    • Bolt In Lump Kits
    • Breather Adaptors
    • Pistons
    • Rods
    • Intakes
    • Mounts
    • Timing Covers
    • Engines
    • Camshafts
    • Shortblocks
    • Engine Stands
    • Harmonic Balancers
    • Bearings-Gaskets-Oil Pump
    • Torque Plate
    • Distributor Blueprinting
    • Carburetors
    • Air Cleaners Used
    • Vehicles
    • 12 Bolts and Parts
  • Inline 6 Articles
    • Me and My Turbo
    • Sissell Literature circa 1988
    • Sunset Chevy
    • 2 HP Per Cubic Inch
    • Cotton Perry
    • Six Abuse
    • Six In a Row Makes it GO
    • Soup of the Day
    • Stovebolts Storm Again
    • Stovebolt Storm Part 2
    • Straight Six Shooter
    • The Buzzin Half Dozen
    • Turbo Tornado
  • Lump Head information
    • General Head Information
    • Inline cylinder head flow
    • Bolt in lump installation instructions
  • Services
  • Gearing Calculator
  • Photos
    • 12 Bolt Pics
    • Inline 6 Pics
    • 292 Turbo EFI
    • Shop Tour
  • Videos
    • 12 Bolt
    • Inline 6
    • Customer Cars
  • Links
  • Tech Tips
  • Wanted
  • About Us
  • Contact
  • Inline Engine Build Ideas
  • Jacob's Journey