I finally found the source of the leak. It turns out it wasn't even an exhaust leak. The source of the sound was caused by the vacuum lines being switched at the top of the fuel pump. It made a phfft phfft sound that sounded a lot like an exhaust leak. Oddly it sounded like it was coming from the passenger side but that wasn't the case. I changed the the passenger side exhaust manifold gasket. I eliminated the heat riser thinking it was the source but it wasn't. I even put the original A intake manifold back with the teapot and that didn't help. I was really stumped. The sound only occurred while accelerating. I couldn't duplicate the sound while the car was standing still and revving the engine. The thought of switching the two vacuum lines around on the fuel pump came out of the blue. Sure enough that solved it. I would have never thought the pump lines could be switched and cause problems.
Finally the problem has been solved!


~DJ~ AKA "Bleach"
1956 Ford Fairlane Town Sedan 30K original miles

My exhaust manifolds aren't leaking as far as I can tell. I can't find any leaks when it's idling. It only makes a pfft pfft pfft sound while driving. I've even checked the heat riser and it moves freely. I'm so stumped but I don't want to take it to a mechanic that I know. it's just kicking my butt.


~DJ~ AKA "Bleach"
1956 Ford Fairlane Town Sedan 30K original miles

56 fairlane: your last post has me scratching my head (am I the only one?)  Are you sure the exhaust leak is from the intake manifold?  The crossover holes if plugged properly shouldn't leak.  Maybe its from the exhaust manifold below?  Some use gaskets on them when retro fitting to avoid leaks.. Also check the intake for a crack somewhere, maybe it was dropped or something like that?. Never heard of one being warped or whatever.. Good luck 


Paul

I replaced the heated choke with the electric one and plugged the two holes and still noticed the same exhaust leak. It looks like I'll need to find someone who can resurface the manifold. If not, I may just go back to the original A manifold and rebuild the teapot.
I guess I took it for granted that the manifold flanges were flat. In all my years of working on cars I've never had any manifold that had a warped flange. I've had cracked exhaust manifolds but never a warped intake. Is this common on B manifolds?



~DJ~ AKA "Bleach"
1956 Ford Fairlane Town Sedan 30K original miles

I had replaced the heat tube in the manifold but it still had that small exhaust leak as before. The manifold surfaces looked flat and didn't have any signs of exhaust soot when I removed it to replace the tube.
I can only figure exhaust is still leaking into the choke tubing since I saw some soot in the choke housing of the carb.
Either way I found a electric choke from a seller in Eugene OR for fairly cheap. I did have to flip the coil in it though since it turned in the opposite direction than my original. Now I just need to plug the heat orifices in the manifold and wire up the cap off the ignition switch with a fuse.


~DJ~ AKA "Bleach"
1956 Ford Fairlane Town Sedan 30K original miles

Don't know if this info will help but.. the exhaust leak may be the choke heat tube inside the crossover being corroded out, a fairly common problem with old 'B" intakes. I believe some of the T. Bird parts suppliers have that replacement heat tube. They may also have the heat tube to carb connection setup. The only hanger on that is the original tubes were coated with an Asbestus material which may not be available now?.  I couldn't find a replacement tube in Canada, when I replaced mine, (a place on e Bay offered to sell me a pk'g of 4) so I made and installed a new complete setup from small copper tubing & copper fitings. For insulation up to the carb I used cotton wrapping that was soaked in Borax to make it fire resistant. So far it seems to be working & holding up o.k.. Note; My carb is also an Autolite 4100, and my exhaust doesn't have a diverter valve as two large parts outfits had no listing for them now + my intake crossover has Truck gaskets, which partly obstruct crossover heat, so I set the choke to not close fully & it seems to work fine. Obviously, I don't drive the car is dead cold of winter..            


Paul

I tapped the Holes and used I think 5/16  or 3/8 Bolts.

  

One more thing, what works best to plug the heat holes in the manifold?


~DJ~ AKA "Bleach"
1956 Ford Fairlane Town Sedan 30K original miles

If You can hear an Exhaust Leak when driving I suspect its not the Choke Setup. I had to resurface both Exhaust Manifold flanges to fix an Exhaust Leak on mine.  

  

Thanks for the tips, I''ll check those out.
Also thanks for fixing the title.


~DJ~ AKA "Bleach"
1956 Ford Fairlane Town Sedan 30K original miles