AUSTIN HEALY 100/4 THRU 3000 PROFILES

            The factory had the cam retarded 5 crankshaft degrees on all the big Healys.  Offset keys are required when grinding a performance cam.  NITRIDING IS STRONGLY RECOMMENDED ON ALL AUSTIN HEALY PERFORMANCE GRINDS.  ROCKER ARM RATIO = 1.45:1 (AVG.)

 

GRIND NO.

SEAT DURATION

.050” DURATION

CAM LIFT

LASH

APPLICATION

STOCK MK. I

230

191

.236

I .012

E .012

3000 MK. I

STOCK 100/4

230

195

.284

I .012

E .012

100/4

STOCK 100S

245

210

.313

I .012

E .012

100 S FACTORY RACE PROFILE

STOCK MK. II

230

191

.236

I .012

E .012

3000 MK. II

STOCK MK. III

252

214

.265

I .012

E .012

3000 MK. III

66-15

264

217

.263

I .014

E .016

100/4 STREET PERFORMANCE

67-18

268

222

.289

I .019

E .021

PERFORMANCE FOR 100/4 & MK. III

685-16

274

230

.295

I .014

E .016

HOT STREET. NITRIDING REQUIRED

70-9

280

228

.263

I .010

E .012

3/4 GRIND FOR 3000 MK. III

72-10

288

235

.293

I .010

E .012

MK. III PERFORMANCE

 

            Longer duration cams are available for all out racing applications.  The edge of the cylinder may need to be relieved for valve to block clearance with cam lifts of .290 or greater.  Nitriding (heat treatment) is required on all but stock grinds.  

 

 

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