See below the stuff from the screamin eagle catalog ,
The replacement of the throttle body and injectors is straight forward and can be done in a few hours , but afterwards you have to tune the bike and do that prefferrably on a dyno while otherwise you are investing a amount of money only to be left with a crappy running bike.
Also be aware of the fact that what comes in must go out so when installing the bigger throttle body the next restriction are the valves so to unleash the whole potential of the bigger throttle body an other camshaft is needed to increase the valve lift and timing , and so you are going from one mod to the next mod and keep on spending money.
By the way ,
There is also a 62 mm Throttle body
A. SCREAMIN’ EAGLE® PRO HIGH-FLOW 58MM EFI THROTTLE BODY – Electronic Throttle*3
The biggest engines deserve the most fuel. This huge 58mm Throttle Body
won’t leave your engine starving for more air. The one-piece throttle body features Electronic Throttle
Control technology. Just add your stock injectors or the Screamin’ Eagle® Pro High-Flow Injector Kit P/N 27796-08
(sold separately). Stock injectors are recommended for engines making up to 100 rear wheel horsepower, Screamin’
Eagle High-Flow injectors are recommended for engines creating greater than 100 rear wheel horsepower. All
EFI-equipped models require ECM calibration (sold separately). For race application only.
27713-08 $399.95
Screamin’ Eagle® Pro High-Flow Injector Kit - 27797-08 Genuine Harley-Davidson® Product
Injectors provide fuel delivery at the rate of 4.9 grams/second, 25% more than Original equipment injectors. Recommended for use with engine configurations making more than 100 rear wheel horsepower. All EFI-equipped models require ECM calibration (sold separately). For race application only.
Fits Twin Cam models equipped with Screamin’ Eagle 58mm EFI Throttle Body P/N 27713-08
27797-08 $141.00