# 1968 oil passage



## JeffW (Aug 30, 2009)

HELP anyone!

I have a 1968 400 block. I have modified the oil system because of necessity.. My question is this. On the block where the filter bolts to the block, there are two holes. One slightly higher than the other. I do know that one comes from the pump to the oil filter and the other goes from the filter back into the blocks oil gallery. I do no know which is which. Can anyone help me? 

Thanks

JeffW


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## BearGFR (Aug 25, 2008)

JeffW said:


> HELP anyone!
> 
> I have a 1968 400 block. I have modified the oil system because of necessity.. My question is this. On the block where the filter bolts to the block, there are two holes. One slightly higher than the other. I do know that one comes from the pump to the oil filter and the other goes from the filter back into the blocks oil gallery. I do no know which is which. Can anyone help me?


Here you go:  Pontiac Oiling System Diagram

Bear


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## Rukee (Feb 8, 2007)

What did you modify, and what was the necessity?


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## JeffW (Aug 30, 2009)

Thanks BearGFR, this will help from guessing. Looks to me the lower block hole is the feed for the filter and the top one is the return. Rukee, the necessity for modifying it is because I have an aftermarket high pressure pump installed and an external PRV from this, I have it plumbed to a remote filter. This feeds a manifold (oil) which I had made up at a machine shop. The manifold has pressure taps to feed a ATI procharger and other accessories such as an fuel pump cut off in case of low oil pressure. I also have taps for the factory pressure warning light and an aftermarket pressure gauge. Thanks guys for your assistance.


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## Rukee (Feb 8, 2007)

Oh-you know we need pictures..... _NOW_!!


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## JeffW (Aug 30, 2009)

Rukee,
There are photos on this web site. Go to photo Gallery ( under classic engines) and at the search box type in my name. (JeffW). Two photos will come up.

If I knew how to get them from there to here I would. Sorry ... I'm a gear head... not a computer geek.


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