New 89 Suburban and a few questions

[77c10diesel]

Well,
  I have added an 89 Suburban to my small collection. It is a 2wd 2500 with 454 and a 400. I filled the tank today and this will be the first time checking the fuel mileage. What should I be expecting? Are there anythings other than the normal(tire pressure, light foot, good tune, etc) that will improve mileage on the 454?
  I got it with the 3rd seat, but the brackets were missing, can I just get brackets from the local yard? What years fit?
The oil pressure gauge sometimes goes to max(past 60), why?
It is real nice and runs great, engine is very solid, but I think the gauge has an issue.

Thanks
Scott

[zieg85]

Since it is your first post I want to be the first to welcome you to the site.  Your mileage should be around 12.

[Captkaos]

Was it equipped with the third seat or did you just get one with it.  The third seat mounts to the floor like a Blazer, so you need those pieces in the floor for it to work.

[77c10diesel]

From what I can tell it came with out the 3rd seat. The PO added the seat but it is not held down. I went to a wreaking yard today and only found a 92+.
Is there anyone that has pictures of what the seat mounts are to look like? Some dimensions of where they are to be placed would help too.
The 92 looked like the parts were welded to the floor, is this true of the pre 91s?
 Any help would be great.
Thanks
Scott

[Captkaos]

There are holes in the floor with cups spot welded to them.  I will try to get pics this weekend, but my burb is currently being used for storing my halftop.

[Lt.Del]

I took this tonight from my 91 GMC V2500 www.delbridge.net/suburban