1978 k30

[derekhisle]

So my truck has a 350 engine with a turbo 400 transmission 410 14 bolt rear end the truck seems to run and drive as it should.But when I hooked it to a trailer, it seemed to have absolutely no power, over about thirty mile an hour In third gear and I was wondering, if anyone had info of how or why it would do this

 

[nvrenuf]

The motor probably made just under 200hp new (before the drivetrain), so it was never a powerhouse.

Bigger tires?

 

[Terlingueno]

How heavy is the trailer?

 

[Frankenchevy]

Smog era 350 in a crew cab longbed loaded down and towing is not going to tow anywhere very quick.

I’d make sure you have a good transmission cooler and keep it around 55 on the highway.

Also make sure it kicks down like it should from third to second.

For perspective, there are 3 cylinder Toyotas that make much more hp and similar amounts of torque. Albeit at different RPM ranges.

 

[HotWheelsBurban]

Smog era 350 in a crew cab longbed loaded down and towing is not going to tow anywhere very quick.

I’d make sure you have a good transmission cooler and keep it around 55 on the highway.

Also make sure it kicks down like it should from third to second.

For perspective, there are 3 cylinder Toyotas that make much more hp and similar amounts of torque. Albeit at different RPM ranges.

That truck needs a little more mojo....my '97 Vortec CCLB one ton has the same rear gear, overdrive (4L80E) and 255 horsepower out of its 350(fuel injection and better flowing heads). I can haul 10K counting the truck, three people, a full bed of car parts and tables, and a 5x8 U Haul trailer with 2500-3000# total weight(trailer empty is 900#). We can do 65 on the highway with this combo, and go faster if the situation warrants. The hardest part is getting it stopped (even with big brakes,13x3.5 rear drums and big rotors up front, you feel the extra weight, especially in the hills near Austin/Central Texas).
If it had a big block like many of the other OBS crews on gmt400.com, or if it was a dually, I could haul more...but this truck sees more city use than hauling on the road (about once, maybe twice a month, most of the year) so a big block and two extra tires don't make financial sense for me. If it gets power upgrades, I could probably get at least 300 horses out of this combo, maybe more. A carbed 350 has a lot of potential; but you might have to spend some $$$. The Vortecs have the aforementioned fuel injection and better flowing heads, plus a roller cam...some of these things would be helpful for a carbed engine.

 

[derekhisle]

The motor probably made just under 200hp new (before the drivetrain), so it was never a powerhouse.

Bigger tires?

It currently has 235/85/16

 

[derekhisle]

How heavy is the trailer?

Not really sure it is 7×16 enclosed trailer with 3/4 in plywood and tandem axle

 

[derekhisle]

Smog era 350 in a crew cab longbed loaded down and towing is not going to tow anywhere very quick.

I’d make sure you have a good transmission cooler and keep it around 55 on the highway.

Also make sure it kicks down like it should from third to second.

For perspective, there are 3 cylinder Toyotas that make much more hp and similar amounts of torque. Albeit at different RPM ranges.

The way that it is geared right now. Even empty.
It starts wrapping out at about 55mph

 

[derekhisle]

That truck needs a little more mojo....my '97 Vortec CCLB one ton has the same rear gear, overdrive (4L80E) and 255 horsepower out of its 350(fuel injection and better flowing heads). I can haul 10K counting the truck, three people, a full bed of car parts and tables, and a 5x8 U Haul trailer with 2500-3000# total weight(trailer empty is 900#). We can do 65 on the highway with this combo, and go faster if the situation warrants. The hardest part is getting it stopped (even with big brakes,13x3.5 rear drums and big rotors up front, you feel the extra weight, especially in the hills near Austin/Central Texas).
If it had a big block like many of the other OBS crews on gmt400.com, or if it was a dually, I could haul more...but this truck sees more city use than hauling on the road (about once, maybe twice a month, most of the year) so a big block and two extra tires don't make financial sense for me. If it gets power upgrades, I could probably get at least 300 horses out of this combo, maybe more. A carbed 350 has a lot of potential; but you might have to spend some $$$. The Vortecs have the aforementioned fuel injection and better flowing heads, plus a roller cam...some of these things would be helpful for a carbed engine.

It was a used 350 carbureted with a 650 elbrock carburetor that was put in it before I got a hold of it.But originally, the truck came with a 400 small block carbureted

 

[Frankenchevy]

The way that it is geared right now. Even empty.
It starts wrapping out at about 55mph

Do you have a tach?

 

[Frankenchevy]

Not really sure it is 7×16 enclosed trailer with 3/4 in plywood and tandem axle

The sticker should say gvwr and payload capacity or trailer weight.

My guess is gvwr is 10k or 7k and the trailer empty is 2000lbs or less.

 

[derekhisle]

Do you have a tach?

No

 

[derekhisle]

The sticker should say gvwr and payload capacity or trailer weight.

My guess is gvwr is 10k or 7k and the trailer empty is 2000lbs or less.

Not really sure to be honest.. I know the truck originally had a 400 small block.
But was blown up before I got it. So they put a 350 in it with unknown miles

 

[75gmck25]

Start out by checking the timing. Stock base timing may be as low as 4 BTDC, but it should handle 12 BTDC without any issue. Then use a dialback timing light to verify you get 18-20 degrees more by about 2500-3000 rpm (total of about 30-32 degrees). That might help a little to wake it up.

Then verify the throttle fully opens the carburetor linkage when you floor it. Somebody had to use a different throttle bracket to fit the Edelbrock and it may be set up poorly.

TH400 also has a mechanical kickdown switch on the pedal, so make sure it’s adjusted so you get 2nd gear when you need it.

 

[derekhisle]

Start out by checking the timing. Stock base timing may be as low as 4 BTDC, but it should handle 12 BTDC without any issue. Then use a dialback timing light to verify you get 18-20 degrees more by about 2500-3000 rpm (total of about 30-32 degrees). That might help a little to wake it up.

Then verify the throttle fully opens the carburetor linkage when you floor it. Somebody had to use a different throttle bracket to fit the Edelbrock and it may be set up poorly.

TH400 also has a mechanical kickdown switch on the pedal, so make sure it’s adjusted so you get 2nd gear when you need it.

I don't have a tac turn on my rpm and to be honest, I'm not really sure what all they did to it.
But I do know when it comes to the kickdown. It has only worked twice since i've had it.And that was only during take off to the floor going up a hill