port and polish 4.8L 706 heads??
07-02-2012, 04:24 PM
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port and polish 4.8L 706 heads?? I was talking to a buddy of mine and he asked my, why dont I just get the 706 heads I have now ported and polished?? Has anyone ever done this??
07-02-2012, 09:58 PM
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No one has ever done this or have a reason to do this?? I just got a 4.8 with less than 70k miles on it. I have read before that the "706" heads have been known to crack but why?? I have plans to get 243 heads when I find a deal, but I really wonder about porting / polishing the 706 heads and putting bigger valves on them...
Anyone care to comment on why or why not???
Anyone care to comment on why or why not???
07-02-2012, 11:45 PM
#3
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The 706 were poor castings. And do sometimes crank and leak coolant very slowly into the oil.
I would just run the set of 243/799 heads. You will lose CR but if you mill them you will get some back.. CR with the 243/799 will be 8.8:1 vs 9.5:1 with the 706.
You could just run a set of 862 heads and port polish them or run a set already cnc'ed 5.3L heads sold by numerous companies.
All the 2007+ Gen IV 4.8/5.3 have the 243/799 heads now anyway.
I would just run the set of 243/799 heads. You will lose CR but if you mill them you will get some back.. CR with the 243/799 will be 8.8:1 vs 9.5:1 with the 706.
You could just run a set of 862 heads and port polish them or run a set already cnc'ed 5.3L heads sold by numerous companies.
All the 2007+ Gen IV 4.8/5.3 have the 243/799 heads now anyway.
