The Stovebolt Site Forums The Shop Area Engine Shop Oil delivery to top of 235 with 1960 block and 1958 head and rockers

I've spent the last two hours reading all the previous posts on this subject. Please help me make sure I understand. My engine had the external "supplemental" oil line running through a hole in the center of the head on the passenger side around to the other side oil chase.

My understanding is that this line supplies oil up to the rocker assembly because of the mismatch between the block and head, etc. I've also read about the center head bolt that is drilled to allow oil to flow through it to the same area.

My question is can I do away with this supplemental line if I use the drilled bolt, or is there something else going on here as well? Thanks for the help.

Have you read my blog post on drilled head bolts?

Yes, I read that twice. My problem is that I don't understand the terminology completely, since I'm not an engine guy. I can make assumptions, but I really don't want to do that. That's why I'm asking the question. It seems that the answer is yes, but I want to make sure before I do something I'll be sorry for later.

The external line was most likely added because the internal oil path was slugged up.
A 1960 engine with 1958 rockers would at the worst supply to much oil to the top end. The drilled head bolt and accompanying plug was designed to limit oil flow in a case like yours.
A drilled head bolt, although not intended for this is sometime used to buy-pass one of the areas that can get plugged up.

The engine has been completely apart and rebuilt. I'm fairly certain there is nothing sludged up. Where might I acquire the bolt and plug? Thanks for the help.

As I mentioned before, the worst thing to happen running 1958 rockers on a 1960 engine is over oiling. I have heard of many people using this set-up with no problem. The main problem I have seen is keeping the valve cover gasket from leaking.

I have a few factory drilled bolts, or they are easy to drill your self, but I doubt you really need one. The head would need to be off to install the plug in the block. I would need to check on the plug size.
PM me if you decide to use one.

Just to summarize to make sure I understand, a 1960 block running a 1958 head and rocker assembly with no plugged oil passages and no drilled head bolt would not need the external oil line. Furthermore, it would tend to deliver too much oil to the rocker assembly likely causing the valve cover to leak.

The drilled head bolt and plug for the oil hole in the top of the block were designed to restrict oil flow to the rockers to correct the over-oiling situation. Is this summary correct?

Before I pull the head back off, I guess I'll run the oil pump with a drill and see what kind of oil flow I get up top. Thanks for your patience.

Sounds like you have it!