Well ,I am no expert, BUT, I have been porting H-D heads since 1978. Anyway , the 'stock' MLS {multi-layer steel} 3 piece,that was the second head gasket that came out in late 07 ,was .040 thick and looked like it was made by Cometic, BUT, it wasn't. I run Cometic .030 hg on every TC ,period ! Ideal squish for the street ,is .028 - .032 and racing gets tighter , .012 - .020 I will tell you want happens inside your motor. Had a 'stock' 2000 FLHT {88"} AND IT PINGED ,detonation. Put on .030 hg ,NO PING. stock hg was .052 ,pistons sat below deck .004 - .007 , so lets say .052 + .005 = .057 now ad in the fact that your motor 'stretchs' any where from .030 - .060 {cyl. grows} so now we ad .052 + .005 + .045 = .097 , YES ? That is a HUGE pocket for air-fuel to 'hide' in. DETONATION !!!!! The reason H-D and everybody else goes with a thick hg is , old 'FART' baby there motors and carbon will build up on the piston and can hit the head after time. Safety ! You want a tight squish band because that is what 're-atomize' your air-fuel mixture , YES ? You don't want 'big' fuel dropletts because they don't burn as well as small 'mist' fuel. Why was the EVO more powerfull than the Shovel ? Same C.I. ? The EVO had a squish band in the heads {D-Shaped} and had squish on one side , TCs have a 'bathtub' {squish} on 2 sides . 110" have a different head that has 'squish on both sides' too , but more on one side that the other. They had to make a 'big' combustion chamber for the 'big' valves { 2.080 intake} and not have valve 'shrouding'. By 'milling' your heads gasket surface ,you will get more squish ,and smaller combustion chamber and a better 'burn' , YES ? Now I am tired and Gunsmoke is on. DEWEY