366 expectations

[chris989]

Hello all,

I narrowed my dump truck choices down and this 1989 GMC 6000 made the cut.

It is a 366, manual, split rear 12' dump. it weighs 10k empty.

I know it is a gasser and will most likely plug along at 6-8 MPG but will i regret it. Can it pull a ~13k trailer. I know it will be a little slow but how slooow. I have never driven a 366.

The other truck is an f650 with a 5.9 cummins. another under powered truck by today's standards.

Any insight would be appreciated, Most of my driving will be near flat. I do live at the base of the mountains so anything out of town will require a few thousand feet of elevation (~5500) at the most.

Thanks,
Chris

[Wyo George]

I'd say 6-8 mpg is optimistic. We had a bus with a 366 and it averaged 5-6 mpg. It'll be geared to pull so it'll move your trailer, but it won't move quickly. If you're in a rig with over 20k lbs combined with an old gas engine you shouldn't be in that much of a hurry anyway

The Cummins will pull better and use a lot less fuel to do so. It's still not going to be a hotrod, but if you're going to be slow you might as well do it while burning less fuel. Depending on the generation of the cummins it'll either be a little better or a lot better, but either way it'd be my choice if I were buying a truck that size.

[Bimus]

I always liked the 366 it is slower at building RPM because of the small intake ports
I drove one in the late 70's and early 80's .
Vaper locking became a problem and a electric fuel pump as added near the gas tanks I think it was due to the additives in the gas in the 80's abought that time new vehicles where all going with in tank fuel pumps.
This truck weighed about 10,000 or more with a flat bed and carry abought 16,000

The electric two speed rear end needed the shift motor rebuilt every so often .
Over all a dependable truck and basic to work on .

[chris989]

Update,

Went to give the truck a second look and a longer test drive. On the drive, the poor truck could not get over 40mph going up a slight grade. It felt like it had a bad miss or plug wires wrong.

When i looked underneath, the passenger exhaust was crushed 90% and the drive crushed ~70%. The exhaust was lower than the front axle and it looks like it has been taking a beating. (Crazy enough,, no leaks).

It looks like it has been that way for a while, not sure if that has cause some valve damage. (exhaust seat/guides) That along with a singing throw-out bearing I decided against it.

It is a shame, it is a cool older truck but When i add up all the little things it will need more than~5k to make it road worthy again.

Thanks for replies,
Chris