S&S Power Pack with 585 Easy Start Chain Drive Cams

Nope. It's only the older Twin Cam 88 engines that require performance valve springs to work with the cams in this kit. The newer bikes all came with better valve spring design straight from the factory that tolerate higher lift cams with ease. The stock components will work find with this kit on your 2011 Street Glide.

No, it's not required. You can certainly retain the stock exhaust components without issue and see an improvement in engine performance. Of course, to maximize the performance potential of this kit, you can only do that with a full exhaust system and an aftermarket air cleaner of some kind. 

No, these kits are designed to work with the remaining OEM or OEM-replacement components on any machine you select from our fit guide. That includes the throttle body and fuel injectors. About the only thing you'll need, assuming you don't already have it, is either upgraded jetting if your bike's carbureted, or a good fuel tuner to properly deliver fuel to the combustion chamber. Yes, this kit will demand more fuel so, a good tune is in order. Other than that, there are no extra parts required.

These kits are designed to work with all the remaining stock components on any machine you select from our fit guide. There's no need to upgrade your bike's crank to fit these components.

There are a few options, but like anything, it really comes down to how far down the rabbit hole you want to go ... eg. tradeoffs. If you have access to a respectable dyno tuner, you're always going to get the most power out of your bike with a good tune. Yes, auto-tune components like the ones listed below are really, REALLY good these - but they'll get you 90% there working with the kind of dramatic change of an S&S Power Pack kit. If you want plug-and-play, something that'll get you pretty close: Vance & Hines Fuelpak FP4 Fuel Tuner - plug it in, download the app, configure the auto tune program and ride. This device is nice if you don't want to visit a dyno tuner and your modifications, existing or planned, don't go beyond an intake, cams and exhaust system. It may not be enough to work with the big bore kit. Dynojet Power Vision 3 Fuel Controller - similar to the FP4, this device allows you to choose from a library of maps on the Dynojet website that'll get you most of the way there, and if you know what you're doing, you can adjust the baseline maps to suit your needs. Still, if you've got a reputable tuner nearby, this is the ticket since maps can easily be made by any Dynojet shop to get the most out of your setup, especially where big bore components are involved. Thunder Heart ThunderMax ECM with Integral Auto Tune System - probably the most versatile of tuners, but support may be limited as fewer shops have experience working with this device. It is capable of the widest range of tuning functionality. A competent tuner would be able to get the most out of your new setup with this kit and keep pace with any changes that you make in the future. For your needs, it's best to speak with a tuner that you trust and see what they like to work with. From that, you can purchase exactly what you need to go with this, or any other engine investments you make!

Yes, this kit is offered in silver and wrinkle black for that 2015 Harley FLD Switchback.

Yes, it would be recommended to have a tuner installed to get the most out of that Power Pack.

You should have no problem using the stock throttle body and injectors with this kit.

S&S states that this kit is not compatible with their Super Stock heads.

Yes, you would just use the stock heads with this Power Pack Kit.