joey.youssef Posted August 26, 2016 Share Posted August 26, 2016 Need some help on what I should do to my 1978 280z. I had to change the head gasket due to coolant leaking into the combustion.... When I sent the head to the machine shop for resurfacing they found that it was cracked near the exhaust valve on cylinder 3... I read that this is common with the N47 heads. I am looking for a replacement head and I found a P79. I was considering buying the P79 head and resurface it along with a valve job. Then I plan on getting new flat top pistons (0.020"-0.040" oversized) and replace the dished pistons I have in my current N42 Block and obviously I will have to bore out the block.. I currently have 2.5" exhaust, headers, K&N intake. Is this the correct step I should take or should I look for N47 or N42 head instead? I plan on using the stock cam. Thanks in Advance Quote Link to comment Share on other sites More sharing options...
malibud Posted August 26, 2016 Share Posted August 26, 2016 p79 with flat tops , n47 n42 with dished. flat tops with the n42 is always debatable some people say its great but you have dial back timing . I have a n47 that was just rebuilt with a couple thousand miles on if interested . but if you have p79 already ... Quote Link to comment Share on other sites More sharing options...
joey.youssef Posted August 26, 2016 Author Share Posted August 26, 2016 I also don't want to have to run super premium fuel since this is a daily driver in the summer..... What is a good compression ratio to try to achieve when I am milling the head deck and boring out the block if I go with this P79 head flat piston block set-up? Quote Link to comment Share on other sites More sharing options...
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