289 cam break in help

iaff284

New Member
Feb 29, 2004
29
0
1
Hey All, I am doing a head/cam/intake swap on a 68’289 and have a question on the cam break in. After reading all the horror stories on lobe flattening during break in I am super nervous to do it. I have a set of GT40P heads with upgraded springs, a performer rpm intake and a comp cams xe262 cam. I am thinking about leaving the stock C80E heads and 2bbl intake on for break in since I know the engine will fire as soon as I hit the key and the stock springs should be way easier on the lifters/lobes. My biggest concern is if the xe262 will pull the pressed in factory studs out of the heads? The cam number is 31-238-3 and here are the specs…..any thoughts

Basic Operating RPM Range:
1,300-5,600
Intake Duration at 050 inch Lift:
218
Exhaust Duration at 050 inch Lift:
224
Duration at 050 inch Lift:
218 int./224 exh.
Advertised Intake Duration:
262
Advertised Exhaust Duration:
270
Advertised Duration:
262 int./270 exh.
Intake Valve Lift with Factory Rocker Arm Ratio:
0.493 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio:
0.500 in.
Valve Lift with Factory Rocker Arm Ratio:
0.493 int./0.500 exh.
Lobe Separation (degrees):
110
 
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