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[oletrucks] Pontiac/GMC oil filters

To: <pontiac-1950s@yahoogroups.com>, <oletrucks@autox.team.net>
Subject: [oletrucks] Pontiac/GMC oil filters
From: "Hanlon, Bill (ISS Houston)" <bill.hanlon@hp.com>
Date: Mon, 11 Jul 2005 11:31:00 -0500
People on the oletrucks e-mail list that don't have GMC (Pontiac) V8s
can ignore this post.  Actually, most of you probably ignore my posts
anyway.

A few years back I was at an automotive parts recycler (junkyard)
removing an HEI ignition from a '77 400 cubic inch Pontiac V8 to put
into my daily driver 57 GMC (Pontiac) 347" V8.  I noticed that the
casting that is used for the spin-on oil filter to the Pontiac 400
mounted to the block in a similar manner to the casting on my truck.  I
bought the 77 casting.  The 77 casting does NOT mount the filter exactly
vertical.  The bottom of the filter tilts back towards the oil pan maybe
10-15 degrees.  Makes for more clearance for exhaust, etc.  I understand
that some Pontiac V8s had castings that hung the filter straight down.

I was tired of dealing with the hard to find and messy to change
cartridge type oil filter in my GMC, so the next time it was due for an
oil change I removed the casting from the block and compared hole
spacing between the old and new.  They were dead on.  I cut a new
gasket, mounted the new casting and borrowed my wife's car for a quick
trip to my FLAPS to get a filter for the 77.  The Fram number for the
new filter was PH-25.  I was a little disappointed in the small size of
the filter, but it sure was easier to deal with than the cartridge
filter.

I've been running that way for 5+ years now.  Recently I heard (on
Performance Years forum) that Napa had a filter that mounted the same as
the PH-25, but had a larger capacity.  It is NAPA Gold 1049.  I bought
one and did some measurements over the weekend and here is what I found:

Fram            NAPA            Original        Measurement     
PH-25           1049            cartridge

2 7/16" 2 7/16" n/a             seal ID 
2 3/4"  2 13/16"        n/a             seal OD**
4"              5 1/8"  9"*             height
3.5"            3.5"            4.5"*           diameter
15.5 oz 26 oz           48 oz*  capacity

*The cartridge numbers are an estimate because I gave mine to a fellow
e-mail list member who needed it a couple of years ago.

**The surface on the casting that the seal contacts is larger than the
OD of the NAPA filter, so this 1/16" difference in seal size has no
effect.

So by changing from the stock cartridge filter to the stock 77 filter
you loose about a quart of oil capacity.  However by changing to the
NAPA 1049 filter you gain 10.5 oz (about 1/3 quart) over the stock 77
filter.

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