Putting a set of S&S 79cc heads on my 96" Fatboy along with 570 es cams. A .030 head gasket and I will be at 10.18:1 and 193 cold cranking. S&S recommends the 570 up to 10.1:1. Will this set up run alright? A .040 gasket will bring me down to 9.98:1 187 cold cranking. I want as much as I can get out of it but still be a good streetable ride.

 

Put the 570EZ in mine back in april. Already had a BB and SE heads and took out SE 257 cams. runs great, really pulls after 60 mph...was hard to start cold; thought that was because of the EZ start cam keeping the exhaust valve open a little longer, until it got to the RPM's required to close, but I changed out the high pressure fuel line in the tank, fuel filter and fuel pump this week, and now it starts like it should, bout 1/2 a turn and it fires up.. the RPMs need to be 950 or above on the EZ start. below that, the little lever that keeps the exhaust valve open starts to work. you can hear the cams click when you shut the bike off and if the RPMS fall...

 

what is your compression?

 

Assuming pistons are OEM flat tops and the heads have compression releases, there should be no issues with either setup. Have you accounted for deck height in your CR calculations? Typically, the OEM pistons are down in the hole .005"-.007" which, in your case with the .030" head gasket will drop static CR down to just a hair over 10:1. Have you accounted for altitude in calculating CCP?

I would opt for the more aggressive setup but your ride; you have to decide.

 

I did account for altitude but knew nothing about deck height. They are stock oem flat top pistons. No compression releases but the cams are S&S ez start cams. I think I will stick with the .030 head gasket. Thanks for the input.

 

go with the .030 gasket,you`ll be fine

 

not sure. was done before I got it but with the SE heads and BB kit it should be around 10:1

 

10.1-1 is perfect for the .570`s

 

I did almost the same thing ur doing. Except I used the screaming eagle MCR heads. Harley says there 76cc. But most people say the mostly come in at 78-79cc. I used the .040 gasket just cuz I was worried if I did have a set at 76cc I might hit a piston. I checked with clay an wasn't close so looking back I wish I had used a .030

So with the 96", SE Heads, and s&s 570 cams I made 92hp 101tq.


Runs real strong and reliable. And beat on a few bikes claiming higher numbers than mine dyno'd at. Def need the compression releases on hot starts.

I think you'll be real happy with ur build.

 

Thanks. I'm getting it put together next week. Cant wait to listen to her on the dyno. ha ha