I've had owned my shovelhead for 15 years and this is my first Twin Cam. So, I have questions.

Question 1 - current exhaust is a Cobra USA 2-into-1. If I replace this with another 2-into-1 exhaust such as a D&D FatCat, will I need a new tune?
Question 2 - The heads are Screamin Eagle "CNC Ported." Can anyone tell me if the intake ports are circular or "D" shaped? Apparently the HPI throttle body intakes will not work with "D" shape intake ports.

thank you

 

google is your friend and images abound.
it isn't rocket science and a few tools to see what you have. i have a set of 88 heads,cyl and pistons all std fit which were take off and the head ports are round.
https://i.ebayimg.com/images/g/d~QAA...1e5/s-l400.jpg

 

FWIW: these S.E. Heads show D shaped EXHAUST ports
Disclaimer the ad copy from the `03 P&A catalog makes no mention of CNC porting and states these are for carb bikes

 

That bike came with Magnetti Morelli fuel injection system- did it also come with a SE Race Tuner, or Power Commander III? There is no support for that system via Power Vision, TTS, Direct Link, Diag4Bike, etc, so pipe change may just be a sound change, but no performance increase.

 

This is the email from Zipper's Performance -

"Tyler,
Some of the HTTC Heads that HD/SE offered had D Shaped ports and require special intake manifolds.
You will need to remove the intake and confirm the intake port in the heads before we can process your order for you.






This is a photo of a D Shaped intake port and you must have the matching manifold.
The Marelli Conversion Kit is not available with a D shaped intake system.

Let me know once you confirm the ports and I will help you move the order forward.

Thanks."

 

Yes, it still has the original Magnetti Morelli with a screamin' eagle intake manifold. The bike currently has this "Techno Research" direct link tune key. I don't know much about Techno Research and have read really good things about ThunderMax. Honestly, I want a pipe change for a new sound. The current Cobra is so mild/muffled, that it does not sound like a 114" Twin Cam. I want a more aggressive sound, as long as it performs the same or better.

 

That is a nice bonus (most of them get lost over the years)! That key allows a tuner with Direct Link Centurian to calibrate the timing & fuel tables in the original ECM for the components installed.