Looking for tips or advice on repairing a leak between the head and LH exhaust manifold on an original '69 442 400 CID, TH400, PS, PB and AC.

Are the steel shim gaskets with bolt locking tabs available? Using any coating on gaskets? Do the manifolds usually warp?

Was thinking of grinding the heads off of the bolts if they resist in order to have something to grab later for extraction. Will the manifold come out with just the bolt heads ground off? Thoughts?

Thanks in advance.

 

If the bolts don't break loose grind the heads as you suggest, Very gentile air hammer(rachet) fineness will break then lose most of the time. Don't see why they wouldn't slide off once the heads are ground. Never had to do that.
Use heat to get them out of the head, carefully.
Check the manifold surface and straighten it if it's warped. A large flat file may do the trick. Or have the surface ground.
I like to use the Felpro gasket(which weren't OEM). Use new hardware and locks. Fusick and Year One sells kits.
Everything gets high temp copper anti-seize on the way back in. Torque by feel if you are seasoned. If not torque ~10% short of the spec. Run it for a few heat cycles and retorque as the gaskets will settle.

 

The head and manifold started life as 2 machined surfaces, no gasket needed. After countless heat cycles, the manifold and head begins to rust and pit, making that precisely machined surface useless. If you can get the head and manifold smooth and flat again, once again, no gasket needed. Otherwise, the small expense of exhaust manifold gaskets is a small price to pay.

Lots of penetrating oil, lots of heat, an air hammer might be helpful, and lots of patience are needed to get broken exhaust hardware out. One of the “joys” of old iron and 50 plus years of “environmental loctite”.

 

Yes the bolt locking tabs are available but they go between the bolt head and the manifold, not between the head and manifold. I would recommend leaving them off, unless you need your car to look factory correct. I had my engine out when I first removed the manifolds back in the early 90's. I put it back together with original bolts and the repop locking tabs. Years later (maybe 2017) I went to remove the manifold on one side and couldn't get the tabs out of the way with the engine in the car and after getting them clear I found the bolt heads had shrunk and had to use a 6pt 13mm socket driven on- just a huge PIA! I put it back together with high quality SAE 3/8-16 bolts from a hardware store, using which seem to have a bigger head. Also used some hi temp anti-seize on threads. NOT what you would want to do with a fully restored show car but much more practical on a fun driver. I don't know if grinding off the heads of the bolts would work with engine in car, (enough room to slide manifold off of ground off bolts?) Good luck, let us know how it goes!