I am working on a 1946 Chevy Pickup truck that currently has a 1954 Chevy 235 installed. I am trying to determine what to do with a vacuum port attached to the exhaust manifold and another line coming out of the head (see photos). Can I block off the vacuum port and seal up the hole in the head? Also does anyone now if someone makes throttle linkage for a conversion like this? I have seen a couple of discussions on line about customizing the existing linkage. Any help would be greatly appreciated.
The first photo looks like the vacuum for the windshield wiper motor, intake manifold, not exhaust. Block it off if you don't have vacuum wipers (which a '46 truck would have) Second photo looks like oil line, possibly for oil pressure gauge.
If your '46 gauge is hooked up, put a pipe plug in the head. Pull the valve cover & check for rocker oiling, as mixing early/late heads & blocks can cause trouble. The throttle linkage is made from the '46 parts, pedal to the pivot - may need bending or lengthened from there. It's fairly easy when you look at it ...
325w is right, that extra fitting on the head is used for rocker oiling. I have one on one of my 235's, but have never seen another like it until now. I can post a pic of the connection on the other end if you want. I would re-connect it, or investigate what killed the internal oiling system. If the inside oil circuit is the same as a stovebolt, it was a very thin tube (1/8" or less), and can get pinched off easily inside the engine.
Just take a die grinder with a cutoff wheel and grind a slot about 1/8 deep through the threads and it will get oil,I had to do that to get oil to the rockers on my 57 235. I eventually went with a drilled head bolt that I found in a motor at the junkyard and when the motor comes out I will take head back off to see just where the problem is so it can be fixed right.
How does the oil get into the rocker shaft? Wouldn't the oil just dribble back down the surface of the head into the drain holes?
There is a passage in the head around the center head bolt where it gets the oil and yes it goes down the drain holes.