402ci Oil Pressure Line Q

[lintcollector]

We bought this project truck in pieces and the oil pressure line is hooked to a sending unit and then extends up to back of the engine block, as expected. There is an extension of about 16" on the end of the line and I have no idea where it should be connected.

I looked at the below prior posts, but only found one for a BB.
http://67-72chevytrucks.com/vboard/s...d.php?t=638710
http://67-72chevytrucks.com/vboard/s...d.php?t=672161

We tried to connect the line to the back of the block and the hole was too big, so it slid right in without using threads.

Does it really matter where I connect the line as it is just a dead end to create pressure?

I've attached a few pics hoping someone can tell me where I should, or if it matters, where I connect the oil pressure line on a 402ci.

Thank you in advance, and sorry for using pdf's for the images...

First pic, top of block, drivers side view showing 2 options.
Second pic, front of block, identical port to the back which was too big
Third pic, driver side block that has 2 potential locations

[SavageC20]

My truck originally had a 402 and now has a 454. Same difference regarding oil pressure line hookups.

The holes in your first picture are for coil mounting brackets (I believe). Because you have an HEI distributor with the coil built into the top of the cap you are not using those holes on your intake.

The hole in your second picture is just a regular hole for mounting brackets and stuff to the cylinder head.

The holes in the third picture are just another spot for mounting stuff to the cylinder head.

All of the holes in your three pictures do not connect to an oil gallery therefore would not suffice for connecting an oil pressure gauge.


The correct spot to mount that metal line would be right above the oil filter. The first link in your post shows the correct location to connect that line.

If the fitting on the metal line is too small you will need a brass adapter similar to the one in the picture.

[SavageC20]

Here is a picture of how mine is attached.

[SavageC20]

Also, be careful not to kink that metal line when bending it to make it reach the port above the oil filter. You can use a deep socket or something round to make bends in the line without kinking it.

[LockDoc]

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Here is the thread that goes with the picture SavageC20 posted.

http://67-72chevytrucks.com/vboard/s...d.php?t=638710

There is also a picture and specs on the Big Block adapter fitting for it. That is why you have the extra 16" piece on the line.

The 1/8" adapter in the picture below then screws into the BB port adapter and the compression sleeve nut on the end of your line screws into it. This fitting is the same for all GM engines. The only difference is that it screws directly into the block on the small block engines and into the port adapter on the big block engines.....

LockDoc