Engine manifold vacuum gauge reading

[joefrazer]

Some of the cylinder head bolts do indeed go into the water jacket. I think the manifold studs do too. I know when I blew a head gasket on the 54, it was due to worn threads on a few of the head bolts that allowed coolant to work its way into the combustion chamber. If you cracked the block, you would have noticed an overheating condition.

A teardown of the engine would be a good idea.

[boatingbill]

Doc: I recently had a valve job on my '51 due to two stuck valves that I could not get loose. The
shop broke one bolt and replaced 5 more due to corrosion. When I picked the car up, the cost was $1. per bolt. I wished that they would have called me because I would have said replace then all.
I think there are 34 of them, so $34. would have been reasonable. Now I wonder if what happened
to you may happen to me, especially on a trip. The head looked like it had never been off and so
all bolts were original.

[Doc]

At this point I cannot say about the bolts. But the engine was a total rebuild in the fall of 2009 and included vat clean complete motor, surface the head, guides, valves, freeze and galley plugs, bearings, bore and hone, deck block, grind crank, pins and bushings, etc. 

[mbflemingkf]

So what hardness or type head bolts are we looking for?  I'm about to replace the head gasket on my 54 as well. Other opinions on replacing all head bolts during this process?

[boatingbill]

I can't read my old ones, but the the new ones have 3 slash marks in the form of a "Y" which means a
grade 5 on the Rockwell hardness scale.

[joefrazer]

You will want to use grade 8 cap screws. The problem is that the factory length is right in between the 2 most common sizes available thru most quality hardware outlets. I had to special order mine and they ran nearly $2 each...which was worth it to me to ensure that I had clean, fresh thread to work with.