MPG while towing?

[Pont406]

I'a getting my 69 long bed c10 into shape. Disk brakes up fron, rebuil front end, rebuil diff with powertrax 4,10 gears, th4oo with 2900 stall very tight converter for now, soon it will have 4l80e with 2000 converter. Class iv hitch. I 'm getting it ready to tow my car on the open trailer. So if I'm getting 12 14mpg empty without overdrive yet, what will it be loaded 7 to9 or worse? Thanks

[special-K]

My guess is 9-10,but I don't even know what engine you have. When you are working a truck the focus becomes what it is doing for you,not economy. It will cost less than paying to have it hauled and hopefully less than driving both. How's that?

[68gmsee]

If you're concerned about the cost, just do a little calculation with the numbers you have and see what you come up with. If you're just wondering what the mpg would be then it becomes more subjective.

Some things that I've noticed make a difference is terrain, tail or headwind, traffic (stop n go), speed and of course weight of what you're towing. I towed a medium sized farm tractor plus some extra farm equipment (weight app 4-5k lbs.) with my 69 chevy (350/350 and 3.08) with no problem and mpg was not significantly affected. Maybe from 15-16 hwy to 12-13 but it was on flat country highway with no head wind or stop and go traffic.

[rsavage]

I am in line with Special K 7-10mpg depending on terrain and speed. The OD won't matter because you won't be towing in OD, but I don't think you should even attempt to tow with your current 2900 rpm stall converter - you will create lots of slippage and heat and heat destroys transmissions. You didn't mention a transmission cooler which is just as important as a good hitch. Like to see a pic of your rig when it's all set up.

[snj8198]

I've been pulling my 12,000lb camper through the mountains. I get 7.5 - 8 mpg. unloaded i get 12mpg in OD on the highway.

I don't mind the mileage. I know I built the truck myself, I don't have a big truck payment each month nor insurance, I don't like the new body styles, I can fix mine if something does go wrong, but the best is seeing the looks on diesel owner faces when i roar past them on the long pulls through the mountain passes!

[Vintage Windmills]

Originally Posted by snj8198

I've been pulling my 12,000lb camper through the mountains. I get 7.5 - 8 mpg. unloaded i get 12mpg in OD on the highway.

I don't mind the mileage. I know I built the truck myself, I don't have a big truck payment each month nor insurance, I don't like the new body styles, I can fix mine if something does go wrong, but the best is seeing the looks on diesel owner faces when i roar past them on the long pulls through the mountain passes!

I was just there in MT too bad you didn't pass us- i would have liked to have seen it pulling up a grade. Not bad mileage either for that much power.

[snj8198]

Originally Posted by Vintage Windmills

I was just there in MT too bad you didn't pass us- i would have liked to have seen it pulling up a grade. Not bad mileage either for that much power.

yep. I read your thread about your trip. Sounds like a neat trip. Wish I could have met you in Missoula.

This motor has a really neat note when pulling the load through the hills. Those cubes through 3" exhaust working hard at 2 grand is super deep and really something to hear!

[Pont406]

Special-K,
Motor is a mild Pontiac 400, after chasis dyno it made 322 hp 347 torque at the wheels and 332hp 360 torque with cut outs open. Last time out it ran 8.6 at 80mph in the 1/8 mile. No times yet since dyno tuning. Here is one of the pulls

Serge F 1969 Chevrolet C10 Pick Up Pontiac 400ci...

It's almost ready to work again. Couple pics of a hitch mock up. I'm not after looks I want this to be functional. Does it stick out too much? Please let me know before I bucher the frame. Thanks

[PAWS 72]

I used to install hitches and work on campers,I like how the hitch sticks out.I wouldn,t go anymore.

I know i,m being picky,I would always disengage OD when pulling any trailer below 60 mph.That helps keep it from shifting between gears and causing trans problems.That came from a transmission man.

[68gmsee]

I wouldn't mess with the integrity of the frame if you can help it. Especially if you intend to do some heavy towing. The hitch looks good to me to as it is.

Just remember to remove the ball and drawbar. Can't tell you how many times I've banged my knee cap...

btw: what hitch did you get? I've been contemplating one for my truck. I know that vendors sell one specifically for our trucks but I'm trying to get one local.

[PAWS 72]

68gmcee back in the 1990's i had mine on a 1978 and then i sold the truck but i took the hitch off. i tried it on the 72 not knowing if it worked but it did so it's been on there since. no drilling .just bolt on.

[PAWS 72]

wait till you have a big equilizer hitch and hit your shin.

[Vintage Windmills]

If your total weight (car+trailer) is under 7500 you should be able to use OD in flat country. I see your in CA so there probably isn't flat country where you are. Rule of thumb for me is if it will hold and not shift much I put in OD. The 4l80e is a good trans for towing. I just pulled 10K through the MT mountains with one and trans temp guage didn't get warm. The engine, well, she got higher than I've seen previously but still not in red range.

[PAWS 72]

Originally Posted by Vintage Windmills

If your total weight (car+trailer) is under 7500 you should be able to use OD in flat country. I see your in CA so there probably isn't flat country where you are. Rule of thumb for me is if it will hold and not shift much I put in OD. The 4l80e is a good trans for towing. I just pulled 10K through the MT mountains with one and trans temp guage didn't get warm. The engine, well, she got higher than I've seen previously but still not in red range.

That's basically what I meant.I've always pulled with a f... because I didn't have the extra money to shell out on a chevy. Always wanted one though.Had a 6 speed the last f... I had and loved it.Both good trucks though

[jeffg1010]

I've got a 350/4L80E combo. I get 13'ish unloaded as a daily driver and 8mpg towing our 7,000 lb camper on average NC terrain. I dont run it in overdrive and she never climbs above 209 degrees. Runs like a champ but bogs down a little on the larger hills. Of course, I don't push it, I just let her go what she wants to go.