I have an ls1 with a fair share of boltons. It has pretty much the entire suspension done except the ta, and sfcs. It's m6 with 275 street tires (nitto drs soon to come). Weekend car/strip car/ fun car/and auto-x

Anyways, what will I notice and how much of a difference.

 

You will not see a lot of change,maybe the rear of the car will feel a little more firm and help you a little with the traction but thats about it.

The main reason to upgrade your torque arm is to throw away the stupid oem design that is connect to the tailshaft ot you transmission.

I ve seen and read a lot of horror stories about broken tailshaft even on a 100% stock f-body.The tailshaft brake then the rear end twist,the rear spring come off...you see the picture.

You dont want a stupid aftermarket TA that will be thicker but will still be connect to the trans.

What you need is the spohn design that relocate the front connecting point to the tunnel brace.Here is the link with pictures on the bottom of the page to explain what i was talking :

http://www.spohn.net/product.cfm?productid=1329

 

I just finished installing an adjustable crossmember mounted torque arm last week and of all the suspension mods. I have done so far, that one is the one that has made the most noticable difference. Previously, the car would fishtail and be all over the place when I would get on it, after installing the arm, I can feel it planting alot harder into the ground and it goes straight. The only downside is that they are not cheap to buy.

 

I got a LT1 putting out about 400 hp think I should go torque arm?

 

Absolutely.