Two Mobil 1 filters are referenced as a good filter. Can anyone tell me the difference between the Mobil 1: M1-302 and M1-301 going in a Mercury racing 565

different thread size would be the main issue 3/4-16 vs 13/16-16

M1-302A is the cross ref for most Merc oil filters

Not 100% sure if its the same for a 565

Here is the OE Filter for the 565

Mercury-Mercruiser 35-881126K01 High Performance Oil Filter

so says:

https://www.mercruiserparts.com/bam/...1361/15970/180

threads are the difference M1-302 is correct filter, however it does not have a bypass. The M1-303 is same as 302 with a bypass valve, does original filter have a bypass valve? Is it better to have the valve than not.

According to the microfiche drawing/parts look up i linked from BAM above, there is a high 30psi bypass (#3 on look up) on the filter head. Therefore, i’d say a non bypass filter would be better. What does the factory filter have ?

Btw: The Napa 1060 (wix51060) are popular on the 525 EFI /700SCI and etc. No relief. Yes on antidrainback. Some like the racing versions: Napa 1060R / Wix 51060R

51060 specs:
https://m.wixfilters.com/Search/PartDetail?PartID=230356%20&Source=WESR

51060R:
https://m.wixfilters.com/Search/Part...20&Source=WESR

Same filter on 500EFI's , so the M1-302A would be correct.