Now that I have my engine running again, I want to change the muffler on it to get a little bit better gas maiilag and performance. Does anyone have any ideas or comments on what kind of muffler to install or not install

Thanks in advance

If you OEM one is still fine I would stick with that.

If you're looking to upgrade, I think the general trend for Isuzu owners is to buy a super dyno max

http://www.independent4x.com/item.jhtml;$sessionid$VA4WNDAAAAEM3TZENUFETIWPERWR JPX0?UCIDs=839915%7C1135358&PRID=976656

contact matt at independent4x to determine your best application.

I use a Flowmaster 50 Series with 3" inlet and outlet. Mereley switching out your muffler won't give you enough gasmilage difference to justify the cost. I don't expect to see any improvements till I get some 3" pipes from the cat back.