Exhaust size

timsresort

Hi, I'm putting a LM7 5.3 in a flatfender (I didn't see a category here in the new forum for CJ LS swaps). I saw you guys say to use 2-1/2" exhaust. Asking around, and I have heard some saying smaller, some say go 3". The motor is stock, and it's a trail rig. Obviously packaging is a concern. What do you think?

Skyler-At-Novak

Hey,

We recommend the 2 1/2" exhaust for the LM7. It seems to be a perfect size for these engines. Our EH001 headers have 2 1/2" collector and have been used in 1000's of LM7 jeep conversions with great success.

https://www.novak-adapt.com/catalog/headers/gm-g3-novak-stainless-headers.html

Let me know if you have any other questions.

Thanks

Skyler At Novak

Austin-At-Novak

2-1/2" is a great size for a stock 5.3. It flows plenty for a mild setup and keeps good torque while being easier to fit under a flatfender. You really only need to step up to 3" if you’re running major upgrades like a cam, boost, or higher RPM tuning.

We also just posted up an Early CJ LS swap discussion. Feel free to check that out!

timsresort

Thanks guys, I have been on the fence about this, and now I'm decided, 2-1/2" it is.

Kelp

Just picked up this post. I have a LS7 going into a 1999 TJ and wondered what headers/exhausts were available. Thanks for any advice.

YJSam

Kelp Thank you for the question. The Gen IV engine will accept the EH001 shorty headers Novak offers. The "Y" pipe and back is suggested custom exhaust work by an exhaust shop.