I am installing a stage 4 kit in my 2014 Street glide. The question i have is the kit has 2 sets of head gaskets. Neither have the same diameter fire ring and they are different thickness.

stock is measures 3.94" across the ring

option 1 part # 16787-99a
measures 3.94" and is .0055 thick

option 2 Part # 16775-99b
measures 3.84" and id .0055 thick as well.

So why did the include 2 different sets of head gaskets and what set do I use. If they were different thickness I would understand the option. I assume i go with the first option as it has a larger fire ring and the combustion chamber is slightly larger but the included install instructions do not speak of a gasket choice.

I prefer to keep it all Harley in an effort to kep compression at the advertised 10.5 : 1.

Thanks for any help

 

Not sure why two gaskets are in the pack but the change from A to B could be many things; change of supplier, elimination of o-ring at oil return, change of material, etc. As a Cometic user, I would not use either one. I would most likely be using a Cometic gasket that is .040" or .030" to improve squish.

Let me ask you a questions though. Why would you use the -99B at 3.84" when your cylinder bore is 3.875"?

 

If you read the instructions they tell you the head gasket is #16787-99a.