- Joined
- Sep 1, 2018
- Posts
- 1,035
- Reaction score
- 2,174
- Location
- Washington State
- First Name
- Craig
- Truck Year
- 1973 (have two), 1985
- Truck Model
- K10, K20, C20
- Engine Size
- 350, 454, 6.2 Detroit
Just for some information, Crower hardens their cam shaft to 62 to 64 rockwell C Also the lifters around 60 to 62. That’s with the premium cam cores. In compairson, HSS cutting tools RC is ~64, pretty hard. Use the zink, I like GM breakin oil, and all breakin oil is $$ but it is insurance. That is a BIG difference from what you measured ~ 50ish. Your oil and engine is contaminated. I would bet you cam is damaged enough where it needs reground. Remove the intake and use a dial indicator and compare the life to the cam spec sheet, A few thou may be OK, and the face finish must be perfect. In any case it's a shame, work, money.
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