What is the best upgrade or the biggest for my 96ci softail custom 2008

 

H-D or S&S cycle bolt-on 110"

 

So I see that people r doing that but when I look in he I only find a 103 upgrade also I dont see any CBC heads for the 103 upgrade

 

Best upgrade or biggest are a loaded question. You can do 103, 106, 107, 110, 117, 124. All comes down to how much you are willing to spend. And when you say best, how do you define that? Most reliable? Peak torque at what RPM range? Peak HP...do you normally go above 6K rpms?

Ask yourself what you are trying to accomplish out of your upgrade then post in the engine mechanical topic section. There are few good builders that can help you.

 

110 without adjusting your bottom end

 

Cam and heads

 

The least expensive way to go is to bore your stock cylinders for a set of pistons to take your cubic inches from 96" to 107". As mentioned you can go up to 110" without boring the cases but you will be buying a cylinder/piston kit which is a few hundred more than buying pistons and boring a stock set of cylinders. Anything larger than that and you will need to bore the cases. I took my 88" to 117" using the stock cases and heads along with a monster big bore kit from Revolution Performance...