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Ok, According to my spec book the factory comp ratio is 9.2 to 1. How muchshould you cut the head to bring it it to 10.0 to 1. I'm building a blaster... and there ain't alot of aftermarket stuff. Thanks...Oldboy
 

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If my calculator is correct you would have to mill .5mm (.020in) off the head. Probably do-able but I don't know if that would be more than the timing belt adjusters would compensate for. It would retard the cam timing some which hurts the low end power.
 

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And if milling, you'd be running the valves that much closer to the pistons... There is probably room for 0.020, but more interference makes cam timing more critical. And I haven't measured the open area at the clearance volume of the head, but most of the head is actually flat, so I would estimate that it would take considerably more than 0.020 to raise the compression (i.e., volume change is only at the open area).. HOwever, a 0.020 thinner gasket.. (like a custom copper sheet), would use the whole area and it would probably work without doing any milling if the piston clearance was sufficient...

INcidently, I find my 1100 pings sometimes on regular anyway, so I am using premium already..
 

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Perhaps an hour on the Randakks web site would give you some good info like aggressive cams, better jetting etc. If you have a few spare bucks, I would think that boring it out & going with oversize pistons would gain you some ponies out of the hole.
 

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If you could find pistons and bore it .5mm (.020in) it would only gain about 90cc. Really not enough to make much difference and wouldn't raise the compression ratio much at all. Besides being very costly.
 

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I asked about hotter cams for older wings and didn't get any info on them like they don't exist. If they do I'd like to know where.,,,
 

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My calculator did goof this morning. You would only gain about 10cc with a .5mm oversize and you probably couldn't find the pistons for that.
 
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