Estimate Hauling Power on "Customs"

I am attempting to estimate the new hauling capabilities of my customized Chevy C60 truck. It originally was considered a “Two-Ton” equipped with a Chevy 366hp engine and a GVW of 18,000lbs. I now have a new Chevy 454 in it with a standard 4-barrel carburetor.

Are there any reference tools out there that can provide some guidelines to estimating how much total hauling power I now have? Im concerned because I have it loaded full and want to tow a vehicle behind it.

Loaded full with what?

Your hauling power is not a function of the engine; it is determined by the suspension, transmission, cooling system and other n on-engine facts.

In spite of the new engine, your truck still has the original 18,000 GVW rating.

I used to drive C60 with 427 in it. What is it loaded with

The gross weight should help you figure it out. What is the weight of the truck with the load that’s on it? If that plus the load you are towing is less than 18,000 pounds, I don’t see much reason for concern.

GVW isn’t calculated with towed weight, is it? I would think most trucks could tow more than the difference between their GVW and their weight.

Hit the scales somewhere and get some data, it will help you come to a better conclusion.Or do it the old fashioned way and hook that vehicle (I conclude it is on a trailer) up and see what kind of control you do or don’t have. What kind of brakes does your trailer have?

Docnick hit the nail on the head.

The frame, the springs, the tires, the axle, etc. were all designed to carry the load originally specified. So unless you modified those as well, the payload capacity is unchanged.

You motor won’t struggle as much under a full load, but you haven’t done anything to increase the hauling and towing capacity of the truck. Engine mods is only one part of what makes up towing capacity. The transmission, and rear end need to modified to handle the greater weights. Then there is frame, springs, and all the suspension and steering parts and mounts. Finally the capacity of the brakes need to be increased.

Whatever your truck was before, is what it is now. Noone can stop you from overloading the vehicle, so it is really up to you isn’t it?

Your hauling capacity in weight will be about the same minus the difference for the weight of the bigger engine. With the add power of the 454 you may notice better acceleration but the over all handling and braking will be just as bad as they were. As mentioned before the hauling capacity is not a bout the engine as much as the vehicle weight, suspension and braking.

Why, are you now having trouble that you didn’t before ?

The rear axle and transmission ratios have an awful lot to do with the ability to tow the specified wieght from a standing stop.
Where in the power band of the 454 does this capability lie ?
The old 366 may have been better suited to heavy loads at low speeds with the ratios in the truck.
You may easily have a bad mismatch between engine power rpms and ratios.

Nope, but if the problem is solved without a lot more figuring it would be nice.

Doc’s right. The chassis, brakes, cooling system, tranny cooling system, and powertrain are bigger issues than the engine itself. And, as Ken suggested, yo umay even have reduced the towing capacity…especially of you’ve used a bigger engine with the original cooling systems.

By the way, you had a “366hp” engine wnd now youo’ve replaced it with a “454” c.i. engine…but that’s coomparing apples and oranges. What’s the HP of the 454? What was the c.i. of the 366hp engine?