Difference in MPG between a car and truck

[68gmsee]

Originally Posted by jablack

Hey 68gmsee, this isn't my thread. I'm just trying to help the guy out.

10/4... I didn't pay attention to the name. The was you posted it I assumed it was Inventive1.

[SS Tim]

Originally Posted by Stocker

I dunno, I had a new '69 El Camino and it only got 10 mph on cross-country trips, on premium fuel.

Come to think of it, the 396/375hp engine, TH400, and 4.10 gears might have had something to do with that......

Now that calls for a picture!

[MARKDTN]

Here is a close answer to your question. I have an '83 K20 that my uncle bought new. 700R4 and 3.42 rear. I bought a 34k mile '91 Corvette L98 TPI engine and 700R4. The case on the Corvette 700R4 was cracked in the wreck. The 700R4 in the truck died at about 140,000 miles so I bought another 89 4x4 case and had it rebuilt with the Corvette parts (not so much because they were Corvette parts but because the later 700R4s are much more reliable and I had a low mileage core). The truck always got 14 city and 17 highway-before and after the transmission. About a year later the cam lost a lobe on the original 350. I put the TPI engine in and my mileage went from 14 to 17 city and 17 to 20 highway. If you can find out what kind of mileage a '91 automatic Corvette gets, you could be close to an answer. The Google mileage I have found is 15 city and 20 highway, but I find that hard to believe that the truck gets better than that. I would like to find someone who has one and ask. The 6-sp would be even better road mileage because of the double overdrive so be careful not to compare to that.

[special-K]

It doesn't matter what gears you have. You can get good mileage from 4.10s...if you drive slower