I was/am getting a little bit of exhaust fume in the cabin and could not detect/see any holes/cracks/deteriorated gaskets in the exhaust system so took the car to my muffler shop guy to check it out. They were able to find the leak...the collector, right where you can't actually see it, in the middle of the 4-pipe cluster as it becomes a single pipe. It's an aftermarket performance header purchased through A T Engineering in New Milford, CT back in '90. It only lasted 32 years! Go figure...
Apparently, replacement headers are as scarce now as hen's teeth. I have searched high and low for a replacement with zero luck.
I'll be taking it back to the muffler shop to evaluate the surrounding mild steel condition to potentially accept weld. 'Anyone have success with this sort of exhaust collector weld repair?

 

Headers | Kirk Racing Products These people make them. Very similar to the AT Engineering

 

Thanks Don!
I have an inquiry into them and will respond back with confirmation one way or the other.
Cheers!

 

This is one Kirk Racing made from a facebook post recently. I have had friends that have got them over the years, they hold up well.

 

If those don't work for you, you can always make your own. I did one last summer for my project. I designed and 3d printed some little header legos to help in the process. For non standard routing they helped a ton. I was planning on doing the routing the other way but the plastic bits quickly showed that there was not enough room. The header runs this way to keep the oil cooler and the pan is modified for additional capacity that also helps keep the oil temps down. No not cutting a hole in the hood. It will run under the car. This is a 78 1500 body with a 1980 1.3L EN from Canada, the 1200 has a shorter nose so dont expect the same layout to work exactly on a 1200 body.

https://www.thingiverse.com/thing:4886707

 

Wow Don. That is an impressive fab job! Nicely done.
The AT Engineering header currently in place has the two down pipes closest to the radiator heat taped and that has worked a treat.
I'm going to try and go with the Kirk Racing system and tape all four down pipes, I think…
Is there any downside to heat-tape wrapping these pipes?

 

The heat wrap will rot a mild steel header in no time.

 

Update: I've put in an order for the Kirk Racing header.
Question regarding exhaust gasket/gasket material: I scoured the e-webs and secured only 2 of the requisite 4 exhaust gaskets (1811-634-000). Is there an alternate part/part number or a better-than-stock gasket material recommended for this application?

Thanks!

 

You are stuck using the stock replacement gaskets unless you want to pay to have them custom cnced out of gasket material. I did a run of 1200 S&S headers 20 years ago and they had some nice gaskets made up for the 20 they sold the group. I think Kirk racing doesn't do that since they make them one at a time.

 

Update: Kirk Racing Header in place. Very nicely done piece of kit...except...
a) a weld was missed during manufacturing but was easily enough corrected (read: prepped and proper bead laid down).
b) when installed, the forward two down tubes unfortunately foul the crossmember ever so slightly. The contact is just enough to set up harmonic vibration at certain lower rpm points. I'm working with my local shop guy to perform some slight (and proper) modification to the cross member to accommodate. *The form factor of the obsolete AT Engineering header tucked backward enough to provide sufficient clearance.