Did you convert the car to V8, 5 lug steering or is it still I6, 4 lug steering?

 

Which JBA set are you attempting to install? I run the 1650SJS mid-length headers and have no clearance issues. You do have to ensure that you have the correct '66 motor mount.

 

New jab headers hitting steering box

Isn't that what they are supposed to do? lol

 

What part number did you use ?
What engine mounts did you use ?
Can you post pictures?
Are they hitting the "box" or the pitman arm?

 

I have the 6651SJT Titanium Coated SS headers from JBA and had to modify them so that they didn't hit the pitman arm on full turn. I used a supported press to indent one tube so that I did not disturb the coating.

 

I post some pics tomorrow I did use 66 motor mounts and these JBA PerFormance Exhaust 1650S Shorty Header, SS, 65-73 Mustang 289/302 the steering box is a stick i6 box but everything else is manual v8 stuff

 

The steering box casting is dimensionally the same I6 or V8 .I'll ask again is it hitting the box or Pitman arm?

 

The box

 

The #8 tube on my 1650s is very close (3/16") to the steering box. I had a clearance issue on the first attempt to install them. Measuring the engine with stock motor mounts showed the engine to be slightly shifted to the driver's side. I elected to install Ron Morris mounts which enabled me to center the engine perfectly and resolve the clearance issue. It's not a cheap fix, but I did not have to dimple any tubes to get them to fit.

 

Don’t know if they use the same manufacturing jig but if they do, the headers shouldn’t hit. The prototype car was a ‘66 GT with P/S, done about 1990. I was there at the time.
Perhaps your engine is farther over on the driver’s side.

 

What is the measurement from shock tower to shock tower? I have 1653SJS? I believe? They're a 351w swap header into a 1965 mustang, they fit perfectly but I know you have to have a minimum clearance of like 36" or something side to side? I wonder if you don't have the minimum. As others have said, you shouldn't have any clearance issues with JBA headers. Maybe try giving them a call and see what they have to say?

 

Are mounts new or worn?

Have you looked into whether lifting the engine slightly and if that would contribute to clearance or worsen fit. Might be as simple as a spacer at mount.

If you have to dent a pipe, "Engine Masters" have at least shown its no real hp loss if it looks less than perfect. If you haven't watched on YouTube, you owe it to yourself before over fretting a primary pipe mod.

 

here is were its hitting

 

I believe that is the #8 tube and that is exactly where I had the interference issue before centering my engine. That is also where I currently measure 3/16" clearance (after centering).

 

I ran into that same issue with my 1650SJS headers. To resolve it, i clearanced the side of the steering box just a bit and also used a big socket and a hammer to slightly dimple the tube that was touching. I'll try to get a pic.

 

Try loosening your motor and transmission mounts and pushing it the tailshaft of the transmission to the right and retighten. It might give you enough clearance.

 

I used a cutoff wheel and removed a portion of the corner of the steering box that was interfering, then lightly repainted it.