Headers: Solving An Oil Filter Clearance Problem

Tube headers provide better exhaust flow than stock log type manifolds. Most Pontiac enthusiasts consider installing headers at one time or another and when they do, they usually face other problems. Not all headers are created equal and the high end headers usually fit better than the cheaper ones,. Yet there are often minor issues coming from their installation. For example, years ago, when I installed Hooker's Super Comp headers (PN 4109) on my 400 engine that resides in my 1979 TA, I faced a clearance problem with removal of the oil filter. Faced with loosening the header bolts and removing the collector bolts ever time I wanted to change the oil and filter didn't make sense. Consequently, I opted for a remote oil filter set up. The one selected was a single unit from Trans Dapt. It has served me well. However, there was another more creative approach and less expensive one I could have taken. [My late father suggested that I modifiy the oil filter adapter. I didn't think that was a good idea. ] Author and fellow enthusiast Jim Hand addressed the same clearance problem and provided PSP with photos showing how one can modifiy the oil filter adapter that will give enough room between the primary tubes to remove and install a stock type oil filter on our traditional Pontiac engines. His advice is below. -- Bill Boyle, webmaster

Additional Clearance between Oil Filter and Header Tubes

We often encounter problems with interference, or not enough space, between the oil filter and header tubes.  There are several different filter adapters that tilt the filter towards or away from the engine. 

We can also make a simple modification that allows the filter to tilt towards the front or rear of the engine.  And many times this will provide necessary clearance to mount or change the filter with the header in place.  And it can allow us to center the filter between header tubes for better air circulation around the filter. 

The method is to elongate the two lower filter adapter mounting holes such that the adapter can pivot forward/rearward on the top mounting bolt.  Note in the photo that the elongation direction/angle needs to match the arc formed from the top bolt hole to the lower ones.  This is marked with a black marker below the pencil tips.  The amount of metal to be removed is dependent on each individual case--however, I suggest a maximum amount of about 1/3rd the hole diameter in either or both directions.  The elongation illustrated in the third photo below allows the filter to move a surprisingly large amount.  

As there is plenty of overlap of the oil holes and gasket between the adapter and the block, this modification is safe and works great. I always wipe a thin coating of RTV on both sides of the gasket before installing, and have never seen a trace of oil leak at the adapter.  Note: It is best to trial fit the header and filter prior to filling the filter with oil, or permanently mounting the filter adapter

The two photos of the filter show how far the lower part can be moved with the minor hole elongation shown on the adapter.  And the holes could be safely cut further if necessary. -- Jim Hand

Adapter pivoted left
Adapter pivoted right
Elongated holes