TTA with AC mockup with GN heads


Active Member
May 25, 2001
I want to run GN heads, as the TTA heads lift at much lower boost levels. There’s plenty of room for the valve cover, and valve cover removal is no issue. There’s only about 2-1/2” clearance between the stock GN header crossover flange and the frame rail, so I have to make room for a proper diameter down pipe. I will install my Spohn K member and see how much additional room I have. I will likely notch the frame rail, would like to run a 3-1/2 down pipe.


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Does anyone know which aftermarket GN 4 bolt headers stay tight to the engine to give the most room for a downpipe? I need all the room I can get between the TTA frame rail and the passenger side header.
3bolt with gn irons champ covers , TA headers but i have a tube K member and hr mounts ,not sure they fit with stock
had to flatten a 3" pipe to slide downpipe between frame
if you want 3" or 3.5 straight pipe youll need to cut into frame and weld in support

this car had a a stage 2 headed motor with 4" downpipe with oncenter 4bolt turbo and custom atr custom header20230731_160849.jpgs
20230731_160833.jpg they went to the ac delete box and notched it ,then tweaked the firewall for pipe to fit

when i dropped the buick iron head 109 in i kept the delete box and reworked the downpipe and had 4" pipes from engine to tail
have since reworked it to all 3" pipes and got functional ac box back


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Thanks for the pics! Yours gives me hope. I have a tubular K member, will install this weekend to see how much room it adds. If needed I will notch the frame rail, and fab up a custom downpipe. I have a tig welder and can spot weld the notch and fabricated downpipe, but someone else will have to finish the welds for me as I really stink at it, lol.
one thing to note is the ta headers crossover is really low hanging on passenger side and really should be modified for tta
i ddint mod it yet and have hit the ground on a good dip


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