what do the experts make of this?

Sounds like you have an exhaust leak from the head to the header. I had that once. New gasket set and I was good.

Uh...buddy.... That is a time consuming, wrench throwing, cursing job!!

4V motor with L/T's hard

2V motor 5spd trans..harder

2V motor auto trans..hardest.

the angle on the heads of the 2 valve is much greater than the 4V and with an auto trans...that big bulky thing gets in the way.
For ease of changing....

For the driver side I would remove the oil filter and the oil adapter, the motor mount and lift the engine. When you finish that side, reinstall your parts.

For the passenger side..this will be tricky. First, pull the starter out...it's a must! Since you already have longtubes, I doubt you can get the motor mount off but with the start out, you MIGHT be able to.

FYI:

My current 96 Cobra has BBK L/T's, I changed the LH motor mount no problem, but the RH mount looked more challenging because of the L/T's. Removing the starter is a must to get to the rear bolt. I don't know if you can get at it with the L/T in the way on that RH side. My 81 Mustang now has the 2001 4.6L 2V engine in there with stock manifolds. Even that, you still need to pull the starter to get the upper motor mount bolt. (Pulling the motor mounts will ease the removal of L/T.s

I paid somebody to fix the right header leak on my old 97 Cobra I had. My regular Mustang shop charged me 125+gasket for the passenger side. In my eyes, it was WORTH EVERY PENNY!!

SVT32VDOHC said:

Uh...buddy.... That is a time consuming, wrench throwing, cursing job!!

4V motor with L/T's hard

2V motor 5spd trans..harder

2V motor auto trans..hardest.

the angle on the heads of the 2 valve is much greater than the 4V and with an auto trans...that big bulky thing gets in the way.
For ease of changing....

For the driver side I would remove the oil filter and the oil adapter, the motor mount and lift the engine. When you finish that side, reinstall your parts.

For the passenger side..this will be tricky. First, pull the starter out...it's a must! Since you already have longtubes, I doubt you can get the motor mount off but with the start out, you MIGHT be able to.

FYI:

My current 96 Cobra has BBK L/T's, I changed the LH motor mount no problem, but the RH mount looked more challenging because of the L/T's. Removing the starter is a must to get to the rear bolt. I don't know if you can get at it with the L/T in the way on that RH side. My 81 Mustang now has the 2001 4.6L 2V engine in there with stock manifolds. Even that, you still need to pull the starter to get the upper motor mount bolt. (Pulling the motor mounts will ease the removal of L/T.s

I paid somebody to fix the right header leak on my old 97 Cobra I had. My regular Mustang shop charged me 125+gasket for the passenger side. In my eyes, it was WORTH EVERY PENNY!!

Click to expand...

My buddy's 2000 GT had the same problem, he took it to a shop and they swapped the exaust gasket and it went away.

Not to steal the thread , but do you have to pull the engine to put a header on our Cobras for the life of me I cannot see how to get to the bolts, or even how to get it in and out

LaserSVT said:

Not to steal the thread , but do you have to pull the engine to put a header on our Cobras for the life of me I cannot see how to get to the bolts, or even how to get it in and out

Click to expand...

Pulling the motor would make it easier to put the headers on. BUT...remember, you cannot get the motor with the L/T's on back in the car.....because you cannot get them around the trans. So, if you do it this way you have to drop the K-frame bolts and pull the motor and trans together that way! It will be a ton of work and I highly discourage doing it this way unless you have a hoist, air tools, a floor jack or two and even a forklift. A buddy would be nice to help you as well. You have to take so much more stuff apart. I did my 4cyl to V8 swap this way last year, and this is the way I dropped my 81 motor and trans, and my 01 motor and trans....then I installed the 01 motor,trans, and K-frame complete into my 81. I had all the stuff I mentioned above and did it by myself. It was a grueling long and exhausting day.

I suggest doing them with the motor in. Like I said, you must remove the starter and both motor mounts..(one side at a time)...and remove the oil filter adapter and oil cooler...(only Cobras have the oil cooler) This gives you much more access because the mounts are in the way and you can jack up the engine. It is still a tight fit.

Honestly, I paid to have mine done back in 2001 because I didn't want to attempt it and did think I could. Now being 25, I know I could for sure...because of the experience I have gotten since then, but I prolly still wouldn't do it because of the time it will take.