I recently purchased a 1955 Olds 98 with the stock 324 engine. I noticed that the exhaust manifolds are attached to the heads using studs and nuts except for the bottom rearmost bolthole on the passenger side exhaust manifold which is attached with a bolt. It just so happens that anti-freeze appears to be weeping from that bolthole. Does that particular bolthole run into a water jacket in the head? Should the exhaust manifolds (originality) be connected with studs at all/any location(s)? Thanks.

 

I just got done a few days ago getting a bunch of exhaust leaks resolved on my 55...

On mine the four outer fasteners were studs, and the two in the middle were bolts. The lower of the two middle bolts was definitely into the water jacket, My block drained when I removed the first one.

Just for your information all of the threaded holes in the head are 3//8 x 16. The threads on the nuts however are fine thread 3/8 x 24. Basically all the nuts on the exhaust are fine thread, but the non-nutted bolts are coarse.

When I took my manifolds off 3 of the 4 studs on the left side came out, and just one did on the right. I figured I was asking for trouble trying to remove the remaining 4 without the heads off the block so I just installed bolts where the studs had previously been and put new nuts on the remaining studs.

 

Thanks for the information. I'll get some plastic tubs ready to catch the anti-freeze before removing the manifold.