18 X™ Series/18°

 

 

 


The BRODIX 18X offers the best of both worlds, 18° horsepower without using expensive shaft rockers or offset lifters.
This head offers a dramatic horsepower increase over the previous 23° cylinder head.
Several advantages of the 18X are intake ports that flow over 320 cfm out-of-the-box, an intake valve size of 2.140, raised intake ports, and shallow combustion chambers. The 18X is an excellent choice for the budget-minded racer who wants to go fast.

Package Heads

Facts and Related Components

• PS CB:
Valve Bowls Blended

• PS MI:
Match Intake Port to BRODIX MG 1800

• PS Valve Job:
Competition Valve Job

• Intake Valves:
2.140 x 5.290 o.a.l. – BR 81050

• Exhaust Valves:
1.600 x 5.300 o.a.l. – BR 81051

• Valve Springs:
1.550 Roller Valve Spring – GA 1000,
240 lb Closed, 550 lb Open,
1.950 Installed Height,
.700 Maximum Lift

• Retainers:
1.550 10° Titanium – MA 2398BR

• Valve Locks:
10° Jumbo – CC 611

• Rocker Studs:
7/16 – BR 716L, AR RRS-4I

• Guide Plates:
5/16 – BR 5160

• Valve Seals:
11/32 – US VS529V

• Torque Heads:
70 ft-lb

• Torque Rocker Studs:
40-45 ft-lb

• Intake Gaskets:
BRODIX MG 1800, COMETIC C3250

• Head Gaskets:
350 – FEL-PRO 1003, COMETIC C5399
400 – FEL-PRO 1004, COMETIC C5403

• Exhaust Gaskets:
Standard-
FEL-PRO 1406, COMETIC C5415
Spread Port-
BRODIX MG 52464 (trim to fit),
COMETIC C5424

• Head Studs:
ARP 234-4727
(12 pt With 3/8 Center Studs)

• Accessory Bolt Holes Are Drilled

• Spark Plug Starting Points:
NGK R5671A-9
for Alcohol
NGK R5671A-8
for Racing Gas

• Spring Pockets:
1.550 Out of the Box, May Be Cut
to 1.625 – No Larger or Deeper

• Valve Angle:
18°

• Angle Milling:
.0065 in Per cc

• Flat Milling:
.0055 in Per cc

• Angle Machining:
Not Available

• Pushrod Slots:
40/60

• Stud Girdle:
40/60 – BR 6440

• Rocker Arms:
Standard 7/16 Roller Rockers, or Shaft System with
40/60 Spacing

• Lifters:
Standard

• Pistons:
Special 18°

• Pushrods:
Special Length

• Intake Face Angle:
BRODIX 10° Standard

• Valve Centerline:
40/60

• Intake Manifold:
HV 1800 / HV 1801

Flow Chart cfm @ 28″ H20

  Valve Size
0.200
0.300
0.400
0.500
0.600
0.650 0.700
18 STD X 2.140 Intake 157 212 260 303 319 321 325
1.600 Exhaust 106 145 179 195 205 209 211
18 SP X 2.140 Intake 157 212 260 303 319 321 325
1.600 Exhaust 122 164 200 217 226 230 233
STS 18 STD X
(CNC Ported)
2.140 Intake 145 214 261 303 328 331 336
1.600 Exhaust 110 154 206 224 231 234 237
STS 18 SP X
(CNC Ported)
2.140 Intake 145 214 261 303 328 331 336
1.600 Exhaust 119 158 196 232 243 247 250

Basic Easy Order Numbers

Part# Easy
Order #
Port
Vol.
Cham.
Vol.
Int/Ext
Valve
Spring Seat
Pressure
Spring
Diam.
Ret.
ST/TI
Per
18 SP X Bare
1180000 244 68         2
**18 SP X Pkg**
1181000 244 68 2.140 / 1.600 240 1.550 TI 2
18 SP X Pkg
1181001 244 58 2.140 / 1.600 240 1.550 TI 2
18 SP X Special
1189000 Custom Order           2
STS 18 SP X Bare
1188000 254 68         2
STS 18 SP X Pkg
1188100 254 68 2.140 / 1.600 240 1.550 TI 2
STS 18 SP X Pkg
1188101 254 60 2.140 / 1.600 240 1.550 TI 2
STS 18 SP X Special
1189001 Custom Order           2
18 STD X Bare
1180001 245 68         2
**18 STD X Pkg**
1181002 245 68 2.140 / 1.600 240 1.550 TI 2
18 STD X Pkg
1181003 245 58 2.140 / 1.600 240 1.550 TI 2
18 STD X Special
1189002 Custom Order           2
STS 18 STD X Bare
1188002 254 68         2
STS 18 STD X Pkg
1188103 254 68 2.140 / 1.600 240 1.550 TI 2
STS 18 STD X Pkg
1188104 254 60 2.140 / 1.600 240 1.550 TI 2
STS 18 STD X Special
1189003 Custom Order           2
18 SP X Combo
9991002 244 68 2.140 / 1.600 240 1.550 TI 1
18 STD X Combo
9991009 245 68 2.140 / 1.600 240 1.550 TI 1
STS 18 STD X Combo
9991005 254 68 2.140 / 1.600 240 1.550 TI 1
STS 18 SP X Combo
9991006 254 68 2.140 / 1.600 240 1.550 TI 1
**Indicates most popular packages sold. **

 

 
 

 
 
 
 
 

 

2 Comments

  1. Larry Smith says:

    A customer wants to know more about the 18 degree x head, people are saying they are no good, I told I never seen a bad 18 degree head, I been porting heads for 36 years, alot was nascar related, I told him how much you want to spend and how fast you want to go, but there are nothing wrong with your heads.

    • Brodix says:

      Larry,

      The 18° Degree X head was set up for the budget minded racer that wants to use standard lifters and standard rockers to make great power. With it’s 244-254 port volumes and 2.140 intake valves. We aren’t sure why anyone would say the head wasn’t any good. They must have had the wrong setup or haven’t used this head before. With all that being said the out-of-the-box 17° Spread Port X will flow 325 intake @ 0.700 and the cnc ported STS 18 SP X 336 Intake @ 0.700. The numbers speak for themselves.

      Thanks!