Front main galley plugs
Originally, all 455's came with core plugs in the front of the main galleys, behind the timing cover. You can see them in the picture of the block on the opening page. This is perfectly adequate for a stock motor, with stock oil pressures. But increasing the pressure in the oil system, and also the simple act of removing the original, staked-in plugs, and pounding new ones in, can pose a problem at times. This modification is not absolutely required, but is a good, cheap insurance policy.
Here are the plugs. You could buy 2 3/8 plugs from the hardware store, and grind one down, but these TA plugs are teflon coated, and ready to install. Doing your own plugs is "penny wise, pound foolish" in my opinion. They are an afterthought considering the cost of any rebuild. TA Part number is 1519, and they are about $6.
Note that one plug is shorter than the other.. here is why.
Note the oil feed hole, right behind the plug, at the arrow. This is the main feed to the passenger side galley, which feeds the the entire engine. Not restricting this hole is obviously important. The short plug goes in on this side, just flush with the face of the block.
Ok, first you have to get the factory plugs out.. DO NOT POUND THEM IN! They will not come out like the core plugs on the side of the block.
There are two methods.
1. Remove the rear galley plugs, and use a long punch to push them out the front.
2. I use the following method.
First, drill the plugs with a 1/4 inch drill.
Then I use a side hammer, with a tapered bit, to grab the plug and pull it out.
Now, knowing that not everyone may have this tool, you can do this by using a big sheetmetal screw, and then levering it out with a side cutter and a screwdriver.
And then we start tapping.
There is no need to drill the hole out, it is the correct size for the 3/8 NPT tap your going to use to thread these holes.
Starting the tap squarely is the biggest challenge in this modification, followed by being careful not to tap the holes too deep. I have seen more than one block, that has come in the shop, with the holes tapped too deep..
I use a carpenter's tri-square to make sure I am tapping the hole square to the face of the block. This tool is available at all home improvement and hardware stores.
Check it side to side, and up and down, and tap it straight!
Go slowly, and I always tap the driver side of the block first, to get the "feel". Remember, I do this 10-15 times a year, but even I have to pay attention, and go slow, to make the job turn out right.
Stop every couple threads, and screw the plug in with a 5/16 allen wrench, you want these plugs just flush with the face of the block.
Here is what your shooting for.
Now move to the other side, keeping in mind that the Passenger side hole uses the short plug, and will require considerably fewer threads.
The finished product.
