Quick Question...

[tpking]

what kinda gas millage would a 1990 gmc sierra 350 with 400 trans get? its a reg cab short bed...

 

[Rifleman]

Poor to crappy unless you drive like grampa.

 

[marccus]

bad to worse!

 

[tpking]

think 15mpg would be capable? what about if i swapped in a 700r?

 

[wrecking-crew]

my buddy gets around 14 avg reg cab longbed 4x4. though motor was taken care of by a racecar driver and rebuilt once.

 

[darkspork]

EPA rates the 1990 2500 at 12 city, 16 highway for 2wd or 11 city 15 highway for 4wd. Whether its good or bad is a matter of perception I suppose.

 

[marccus]

if you drive a lot. not that great, i had a 3/4 tod, 2wd with a 3 speed, i didn't drive muck, so it wasnt bad.but probably 12-14mpg.

 

[tpking]

well 99% of my driving is highway so if i can squeeze out 15mpg i might go buy me a new truck tomorrow .. how much of boost would it be to the mpgs with a 700r?

 

[wrecking-crew]

get a ranger again

 

[tpking]

find me a good running ranger that doesnt have any rust on it for $700 and i will .. if i had $2000 i would buy my brothers ranger thats lifted 6inchs on 33's but i dont so chevy has to do

 

[Will]

What is the GVWR on that truck? It must be a 2500 or 3500 with a 8,600#+ weight rating to have a TH400. But I didn't think that came in a short bed. Any 1500 or 2500 7,200# GVWR and below should already have the 700r4.

 

[tpking]

it had the 700r in it but someone has swapped it out for the 400

 

[tpking]

no more input? gonna go drive it tomorrow and prolly end up driving it home. doesnt have any rust or anything just needs paint ..

 

[RustedRanger]

If I remember right a 700R4 will add 15-20 % mpg. I had a 88 4X4 half ton that I put a crate 350 with a smog legal roller cam,Holley 650 TBI,K&N air filter with the lid flipped,coated shorty headers,no cat,and a 3 inch glass pack and it would get 20 mpg,it also had the 700R4 but it died and I had to get it rebuilt. Also I had to drive like a granny, when I would pass someone I could watch the needle go down on the gas gauge and it had a 34 gallon tank.

 

[darkspork]

no more input? gonna go drive it tomorrow and prolly end up driving it home. doesnt have any rust or anything just needs paint ..

The 350s are pretty good engines. If you want the truck don't sweat the gas mileage too much. I think you'd be better off keeping the 400 transmission than you would be swapping in a 700r. A friend of mine has a Sierra and I remember seeing it sitting on the highway for a couple days, asked him why "transmission failed". From my understanding there are enough people who have problems with those transmission that I wouldn't poke it with a stick. The 700r was probably swapped for the 400 for a reason. Just my $0.02