Has anyone had trouble with using stock head gaskets with higher compression? I am very close to pulling the trigger on a freshening up of my '02 Road King with HD 95" kit (now has 57,000 miles). Will be using KB dome pistons, which, when used with stock, .055 head gaskets, will keep the compression to 10.0:1. If I use the thinner Cometic metal gaskets, which are around .027 (compressed), compression will be closer to 10.5 or maybe a little higher. Would like to keep it no higher than 10.1 for various reasons. If the stock gaskets will hold up that will save me the hassle of machining the dome (which is solid, spoke to tech support at KB, this is definitely an option if necessary). So, if the stock gaskets will hold up I'd much prefer to do that. Any thoughts?

 

Cometic will make any gasket you like. Just call.

I would keep the squish between .030 to .040 which means incease the head volume or decrease the dome volume.

You may know this but it is not your static compression that counts, it is your dynamic compression that counts. Depending on your came intake timing you can run 10.5:1 with no problems. Many do. A later intake close will effectively reduce your compression.

B

 

Thanks, B. I know that in a general way, but don't really know what tolerable dynamic compression ratio values are. I was screwing around with the compression calculator on the Keith Black piston website and found that the dynamic numbers (all you have to do is enter your intake closing event in addition to the other data) are considerably different (lower) than the static. I'll be running S&S 585G cams, intake closes at 45 deg. My local hot rod bike shop owner tellls me I can run as low as 9.5 :1 and as high as 10.5:1 static with this cam. I want to go as high as possible without sacrificing streetability and reliability. So I figured if I keep it around 10.1 I probably will get pretty good bang for the buck but still be able to jump on it and ride to Tennessee, or West Virginia, or wherever.