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Old 05-10-2019, 01:01 PM
tooski tooski is offline
Chief Ponti-yacker
 
Join Date: Oct 2010
Location: Thunder Bay, Ontario
Posts: 717
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The info I have read on the forums indicate that no way a cam with the specs of the HC-02 should be causing detonation at 9.77. Unless it was poorly installed. Which it was. By me. At the time (mid 80's) I had no idea about cam degreeing. Turns out it ended up 4° retarded. I am thinking that would significantly affect the DCR leading to detonation.
I can see the engine not being happy with the smaller cam even if it was installed correctly. Hence the head change to lower the compression. I think 8.1 to 8.4 is a bit low.
As Jay posted I believe I will need to go to a custom piston (Autotec) because of compression distance. Why put those nice new forged pistons on old cast rods? So, new full floating forged rods would also be in order.

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75 Firebird
68 Firebird 400 RAIII
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