i'm thnking of buying ont of these calibers for my encore to hunt hogs. i know both will have plentyof knockdown but which will give the best performance in penetration and overall stopping power. i don't handload so both will be factory ammo probably from bass pro.there will be an occasional deer hunt thrown in for these guns but where i hunt a scope will not be needed i hunt some pretty thick stuff maybe 50-75 yards is all i could see to shoot and be sure of a good hit. i'm pretty fair shot with open sights so i'm not worried about the vision or seeing the target.

Grumpy - both of these cartridges are a heck of a lot of gun for deer. But both should perform well on hogs. IMO I would probably opt for the .45-70 even though the 375 is also a good choice. You may have trouble finding ammo for the 375 JDJ.
I've taken 3 bear with my .45-70 Guide Gun using 300 gr HPs and it has performed admirably. The first 2 were with factory ammo and the last one was with handloaded ammo.

Either will work fine. If you don't handload get the .45-70. There are lots of different factory loads out there.

I've been hearding alot lately on the 375JDJ. Can someone post up some numbers to go along with this cartridge? None of my loading books list it.

You can get some data here http://www.hodgdon.com/data/pistol/375jdj.php
http://www.accuratepowder.com/loaddata_caliber_handgun_standard_375cal.htm