New oil filter is smaller than the old one. Why?

Bought the high end Mobil oil filter which was $10. It is 2/3 as tall as the old Fram one. Is there a reason it is smaller? I figure it will hold less oil but it can't be enough that could matter.

Not a big deal, Actually if you look at the original replacement AC Delco, I bet its the same size as the Mobile filter you have now. The only major thing to worry about is if the gasket and threads are the same. Filter sizes vary by brands, and its more convienent to just throw 5 quarts of oil in than 4 and a half, so many replacement brands are 1/2 a quart bigger than stock in cases where the stock is short. Just line your gasket up to make sure its the same and then it should thread on like normal. Just dont forget and overfill the engine if your used to the other tall filters.

Most manufacturers make both a "short" and "long" version of the filter that fits the LT1. If you just look up the part # in their catalog for you car, they are going to list the short version, because that matches the PF-25 filter that was on it when it left the factory.

Get a filter for a late 80s through mid 90s 350 truck, I believe it's M1-301 (or is it 311) it's long and fits the LT1 perfectly.

I use the Mobil1 M1-302 for my LT1.

AC Delco PF1218 its the longer version of the PF454 that is stock

if you have the factory oil cooler i would recommend the PF1218 since its slightly shorter than the PH5 i believe it is in fram

anyway with the factory oil cooler the slightly shorter PF1218 keeps the bottom of the filter comfortably above the bottom of the oil pan and out of harms way

Ditto. DO NOT use the long filter if it is the lowest thing sticking down in the front of the car. They can be easily knocked off. Your filter should not stick below the pan or cross-member.

Get a filter for a late 80s through mid 90s 350 truck, I believe it's M1-301 (or is it 311) it's long and fits the LT1 perfectly.

Perfectly? I cant even get my favorite filter on: the K&N (it's just a tiny bit
longer than the stock Delco), much less one of the extra-long filters. Why?
Because of the headers.

That's why I've ordered a remote-oil-filter kit.

Now, is it better to use the biggest oil filter possible? I would think more material would be a good thing right? Any ideas?

Now, is it better to use the biggest oil filter possible? I would think more material would be a good thing right? Any ideas?

Obviously, more filter area would equate to better and longer-lasting
filtration. A smaller filter would suggest that it has to be changed more
frequently than a larger filter.

The second thing that should be obvious is that a better quality filter (K&R)
will outdo (regardless of length) a lesser quality filter (Fram).