The swap is scheduled. The rebuild LS7 with forged internals (non-dished pistons), Katech torquer LS7 cam, and LS7 heads is going into the 98 TA convertible. I am using the stock LS7 intake with a NW92mm TB. My goal is a NA street/strip car with around 500 RWHP and 475 RWT. I am focusing on low end torque since the car will likely never see the drag strip. I am planning to purchase Kooks LT's - the car already has an off road Y-pipe and Magnaflow cat back. I have read that the "standard" round LS1/LS3/LS6 headers will perform about as well as the more expensive "D" shaped LS7 headers. So, I planned to order standard 1 and 7/8" Kooks headers. Does anyone have input on this issue? Also, is there an advantage to using stepped 1 and 3/4 to 1 and 7/8 or stepped 1 and 7/8 to 2" headers for my application?

 

Any input???

 

Doubt there will be loss going to round headers instead of D-shaped, but if I were you I'd go with 2" headers. I'm running 1 7/8" on a 6.0 with stock LS7 cam, you should go bigger.

 

honestly doubt it. if you look at it, the LS6 and all rectangle port heads have D-shaped exhaust ports and this is the first thread I have seen asking about D-shaped headers.

 

I'm running the LS1 flanged Kooks on my LS7 445 and i doubt that it is hurting me anything. If i were you i would at least go to the stepped 1 7/8 to 2 inch. You won't loose anything and down the road you'll have them if you ever add some more go fast goodies!

 

If you haven't ordered the headers yet PM me with what you need, maybe I can save you a few bucks

 

I have the kooks 1 7/8 on my z06, ls7 427. It puts 600 to the wheels with those headers. The exhaust system behind the headers is the most important part on a street car.