[wagonman76]

Thanks for the replies everyone. This seems like quite a nice place.

How about the tires I am thinking of swapping? Has anyone gotten any gains from a tire that is 10mm narrower, or is it probably not worth the $40 to change them over?

Ive thought about a manual trans swap. A few other a-body enthusiasts have done it. The parts are very hard to find. Suitable gearboxes and shifters were available from a few other GM lines, and axles can be mixed and matched from other lines to fit. The hardest part to find is the pedal assembly, since manual trans a-bodies were extremely rare. It is a lot of work and I may or may not actually do it someday. The stick would be fun for summertime though.

Another thing I would like to try if it was easier would to be swap the final drive to 3.06, 2.84 would be probably pushing it. The only thing is with the 440T4 it is easier to swap the entire transaxle which is a ton of work. On the 4T60E you can just pull the passenger side axle and cover and swap the final drive very easily. I might try swapping the van tires/rims on it for a trip and as long as they dont rub, thatll fake a 3.13 final drive and I can see how it does.

My mileage numbers are what I can get pretty much every time. My daughter's mom lives 175 miles downstate so I run down there and back average once a week for most of the year, once every 2-3 weeks in the summer. The driving is about 90% highway.

The Scangauge type unit for OBDI sounds interesting. Ill be reading up it some more.

I have built an O2 sensor modifier and MAP/TPS modifier circuit. I have messed with them a bit but mileage just goes down when I try to lean it out so I quit doing that. I be interested in tuning these engines to run leaner, even a 10% gain would be nice.