The Type 'A' buses on the Chevy/GMC chassis with the 6.0L/6L80 or 6.0L/8L80 power package is about as good as it gets. Depending upon load and speed they will get 12-14 MPG with an honest 13 MPG average.
The Type 'A' buses on the Ford chassis with the V-10/E4OD (or later variant) will get 10-12 MPG with an honest 11 MPG average.
The Type 'A' buses on the Chevy/GMC chassis with the Duramax will climb hills faster than just about any bus but the fuel mileage isn't that much better. Figure on 13-15 MPG with an honest 14 MPG average.
The Type 'A' buses on the Ford chassis with the 6.0L diesel usually didn't go far enough to figure out fuel mileage. Unless the engine was bullet proofed it is a $5K-$10K repair waiting to happen. Fuel miles was in the 12-14 MPG range.
The Type 'A' buses on the Ford chassis with the 7.3L got 11-15 MPG depending on weight, speed, and shape of the bus. We always got 1-2 MPG better on our buses that were more aerodynamic than the brick shaped buses.
Type 'A' buses on the Ford chassis with the 460 gas V-8 got 5-9 MPG with the honest average closer to 5 MPG than to 9 MPG.
The Type 'A' buses on the Chevy/GMC chassis with the 6.2L diesel V-8 were underpowered, slow, noisy, and not very fuel efficient. 10-14 MPG. The engines were pretty stout but underpowered in a bus.
The Type 'A' buses on the Chevy/GMC chassis with the 6.5L turbo diesel V-8 were marginally better on fuel economy at 12-16 MPG with an honest 14 MPG in there somewhere. The power was better than the 6.2L but it was no barn burner. The new 6.0L gas V-8 has more power and torque than either the 6.2 or the 6.5. The downside with either the 6.2 or the 6.5 is GM stopped supporting any parts for the them some time ago and virtually nothing is available aftermarket because so few G-models came with the turbo diesel. There are some dealer only parts and pieces that do need replacing over time that are getting into unicorn status with prices to match.
|