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Towing with a I6

Hossbaby50

Hossbaby50

3/4 ton status
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Sep 1, 2001
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Peoria, AZ
I am wondering if it is really a decent option to tow a K5 on a trailer or flat tow it with a truck with an I6 motor (250 or 292).

I have been thinking about buying an older 72 or prior C20 Chevy with an I6 and a 4spd for DDing and sometimes towing the K5 around. I want the I6 because it is a stout little motor that gets good mileage unlike my K5.

If I spent some money beefing up an I6 motor with a 2 barrel manifold, headers, exhaust, and HEI how well will it do? I would probably run 4.56 gears and stock size tires.

My goal is to get a dependable DD truck that gets decent mileage that can tow the K5. I am thinking that the old C20 might be a good option until I can afford to get a used Cummins or Pstroke in a few years.

I know even on flat ground the best I could hope to tow at would be 55-65 MPH. That is no big deal. The question is would it be able to sustain a decent speed 35+ MPH in the mountains of Colorado if I was towing to Durango or Moab from Denver? Thanks

Harley
 
you wont be happy with the mileage or towing ability... either with the 250 or 292 (which gets as bad if not worse mileage than a v8)...
the 250 is way down on power... the 292 will be hard pressed to maintain the speed you want and not suck gas like a dog....
A well built v8 tuned and running properly will equal or surpass the mileage of these motors....
I had a new 1976 k10 with the 250 and it got at best 14... and couldnt pull
I had a c20 with the 292 and it was horrible...like 12-14... it could pull but the mileage diasppeared immediately

now.. an i6 cummins..... now your talking.... 20mpg and hard charging
 
I think it could do the job. My Dad had a '68 3/4 ton with the 250, 4 speed and 4.56's and the stuff he pulled around was jaw dropping. It never got there first, but it always got there. He was a bricklayer and did not hesitate to abuse the truck well beyond it's intended limits.

Fuel mileage wasn't great though...

Have you considered a C20 or C30 with a 6.2 and a SM465? They are the 'J' code trucks and came with 4.10's and ~29" tires. I think it'd do a great job and get much better mileage than a 250 or 292. Just my opinion though...and you know it's a little biased. :)

Rene
 
I am not that worried about mileage while towing, I know that will suck. I want to get decent mileage while I am DD'ing it which will be most of what its duties would be. But once in awhile I would like to drag my K5 to Moab or other places in Colorado to get some good wheeling in. All the hard stuff will be over 3 hours one way to get to in Colorado so I don't want to drive my truck there and back. Otherwise you can't wheel like you want to. You have to worry about getting home still.

I kinda want to get an older truck pre-73 because I like the older lines. I would really like a 60-66 if possible. I have always liked those trucks. If a C20 or C30 popped up for the right price with a 6.2 I would consider it but I don't think I would seek one out.

Harley
 
I wouldn't buy an I6 with the intention of ever towing anything but around town with it. My warmed up 305 is marginal... even the best I6 would be around a hundred horses short of my 305.

I got ~11mpg towing my trailer with the 305... I'm willing to bet if I were to drive a 2wd truck with small tires and no lift I'd get close to 20mpg driving around.
 
I don't know how "warmed" your 305 is but I know the 305 that was in my truck before my 350 went in was a DOG. It was pretty stock except exhaust and an intake manifold though. My roommate has a stock 250 I-6 in his 66 Chevy C10 that would run circles around my old 305.

My roommates truck gets about 18mpg with a 4spd, 31" tires and 4.56 gears.

Harley
 
Not a chevy, but still.

One of our old work trucks was a ford with a wide ration T-18 and a 300 I-6. That thing may not have been the fastest tow rig, but it towed circles arround the supposed to be replacement 2003 f-150 with a 5.4. I convinced my boss to keep that old 300 just to tow the trailer. It was down on HP, but had great low end torque.

My dad used to tow with a '69 C20 with a 292, he said it did well, but was pretty bad on fuel for being only a 6. Dont have much more information than that, he sold that before i was arround.
 
Hossbaby50 said:
I am not that worried about mileage while towing, I know that will suck. I want to get decent mileage while I am DD'ing it which will be most of what its duties would be. But once in awhile I would like to drag my K5 to Moab or other places in Colorado to get some good wheeling in. All the hard stuff will be over 3 hours one way to get to in Colorado so I don't want to drive my truck there and back. Otherwise you can't wheel like you want to. You have to worry about getting home still.

I kinda want to get an older truck pre-73 because I like the older lines. I would really like a 60-66 if possible. I have always liked those trucks. If a C20 or C30 popped up for the right price with a 6.2 I would consider it but I don't think I would seek one out.

Harley
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unless you completely went thru the drivetrain/brakes, i wouldnt suggest using a 60-66 truck for a long distance tow vehicle. it can be done, get a 3/4 ton, swap in disk brakes/dual master cylinder setup to make it somewhat safe.
they could be had with a v6 (i think its 305ci) which some people like. personally i'd recomend swaping in a 350 if u want any reliability.thats what i did, but i get crappy mileage causs i cant keep my foot out of it. if your willing to drop a bunch of money into it, a 60-66 truck would be awesome.

another option is getting a newer truck73-87 and swap a 60-66 body on. lots of work but would be the perfect mix between classic looks and good tow rig
 
250 I6 is a great towing package... It has more torque stock than a 305, and yeah... it's got less horsies, but a stock 305 only had between 145 and 175 hp to begin with in the trucks depending on the year (I read that somewhere, so don't quote me)

I wouldn't buy an I6 with the intention of ever towing anything but around town with it. My warmed up 305 is marginal... even the best I6 would be around a hundred horses short of my 305.
Click to expand...

so you are saying that the I6 only had like 45-75 hp??

That is doubtful... even a hopped up 305 is only making at most 250hp unless you put enough money into it to build a 350... Most I6 engines put out more power per cube than a V8 when you look at their torque AND horsepower, and not just one or the other. Even the Ford 200CI I6 was a torque powerhouse, though I wouldn't recommend it in a truck.

My 250I6 that I had in my Maverick could likely put down a good 130-150hp, and it had no real mods on it except the 2bbl carb option from the factory. Like a Grabber that could pull... amazing little machine, it ran forever, and is still running wherever it is with likely 200k + miles on it. It's almost like running a diesel for the amount of power you get out of them, and like I said in another thread, 12 gallons lasted a good week or more of city driving... 200+ miles to the tank was easy.

The I6 250 Chevy is an awesome towing motor, as long as it has the proper drivetrain behind it. You'll want to run it as a manual too for the extra torque you can get out of it.
 
Hossbaby50 said:
I don't know how "warmed" your 305 is but I know the 305 that was in my truck before my 350 went in was a DOG. It was pretty stock except exhaust and an intake manifold though. My roommate has a stock 250 I-6 in his 66 Chevy C10 that would run circles around my old 305.

My roommates truck gets about 18mpg with a 4spd, 31" tires and 4.56 gears.

Harley
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190hp@5600 to the asphalt. That's more than any carbed 350 ever put in these trucks ever made at the crank. It's embarrassing, but I've got $700 tied up in it. I didn't have a spare 350 when I needed to have a block in getting machined so I could swap motors over spring break.

Before the rebuild it was a dog. Most 305s were rated for 155hp at the crank or less... and most of them made less. I ended up breaking several ring lands which is why it got pulled.

About all you can get out of a 305 is 280-290hp without either going with a really wild cam or aftermarket heads.

At around 65mph I get my best gas mileage. High vacuum, right in the sweet spot in torque, and not spinning fast enough to move a lot of air. Get around 17-18. I usually use 31-32 gallons of gas to go 477 miles. I usually burn up nearly 20 gallons on the expressway at 80mph... the rest is going an equal distance at 62-63.

But anyway, it's not an ideal tow motor but mine seems to do just fine (compared to any other non-vortec SBC). But if I want any "power" I have to spin it at 3,000rpm or faster.
 
For what it's worth

My father-in-law and I towed my cuda on a car trailer 1800miles from Virginia to Colorado with a '95 Chevy 1/2ton with the 4.3L and standard tranny. Not sure how the 4.3 and I6 compare, but I'll bet it's reasonably close. The cuda only ways about 3800# though.

Point is I think you could do it with a standard and the right gearing. I do think I would want to upgrade to discs on the front.

On a side note, my first vehicle was a '64 Chevy pickup. Wish I had that truck back. Some day I'm going to get another.
 
tRustyK5 said:
The Mav would have had a 200 or a 240.

Rene
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Not so, the 240 is the same block as a 300, has separate intake manifold, not cast in place like the 250. The 250 is a dirrect descendant of the old 144 Falcon engine, the 240 was built for full size cars and trucks.
 
3 on the tree said:
Not so, the 240 is the same block as a 300, has separate intake manifold, not cast in place like the 250. The 250 is a dirrect descendant of the old 144 Falcon engine, the 240 was built for full size cars and trucks.
Click to expand...


I was gonna say that... you beat me to it...
 
I've done some time towing with a 68 C50 dump truck complete with SM420, 2spd rearend, and 292 that burned propane back in the day. Granted, the extra weight of the truck hurt it performance wise, but the 2spd rearend lets you split shift and keep the engine closer to it's sweet spot. It will pull with all it has all day long, which is a conincidence since that's exactly how long you'll be pulling. It's not my first choice for towing, but I have not doubts a 292 would get the job done. I've never worked on one, but a local clutch rebuilder told me the 292's use a special flywheel with an extra bolt holding it to the crank becuase the torque would shear the bolts in half.
 
Not sure if I'd reccomend a six....

I've had several GM six cylinder trucks,the most recent one my 79 C10 "Bonanza"--it WAS a 250 "camel humper" with a 2 bbl rochester 2SE carb,they were lousy carbs,I put an adapter an d a 600 cfm Edelbrock performer on it,but disconected the secondaries--it was too big for the motor,but it ran well on the primary barrels--it got about 13-15 mpg most of the time,but it wasn't exactly a drag racer off the line...I dont think I'd have been happy using it to lug a slide in camper around,or tow a good sized trailer either...its easy to get killed here if you cant keep up with the traffic..they run you right over!

The six lost a peice of the #6 piston rather suddenly last summer,and it was the end of it at 113,000 miles--the older 250's with the "non integral" heads were much better motors than the "camel humpers" with the 2 barrel carbs..

I got an 86 305 out of a van and put that in it rather than fix the six,or put another inline in it--it was cheaper for a V8,and the motor I got only needed an oilpan and oil pump and timing chain and gears--the truck now goes MUCH faster than before,will even chirp 2nd gear now,and I have to keep a light foot on the gas pedal in the rain,or it will spin one tire forever...The six had good low end power,but runs out of steam at higher rpms--I had difficulty maintaining 55 mph EMPTY on a few hills in NH!!

The 292 is a great torque engine,they put them in dump trucks and step-vans a lot--they used 6 bolts on the torque converter for more strength,and often a TH400 was used behind them also!--a hard to kill combo--but gas mileage is awful on a 292--10-12 mpg was all I have ever gotten with the one barrel carbs they had--several guys who had them reported similar gas mileage--a 350 V8 is better on gas in many cases!!.-But the sixes were a rugged long lasting engine in most cases--

I had a 235 six in a 56 3200 series truck--that motor was torquey too,many guys thought it had a 283 in it until I openned the hood!--it was a gas hog too though..hard to find now in most areas--chevy used them until 1962..

If you want a 60-66 style truck,the 305 V6 and 351 V6 were optional for them--you can still find them in many school busses--they were one of GM's best engines,but they also were not very fuel efficient..but outlasted most of the trucks they put them in...

I'd say a 283 or 327 would be ideal for a truck that year with lower rear end gears,they love to rev,and will deliver 15-20 mpg doing it!--they will tow better than a six will,and beat it in the gas mileage department too...

Of course a big block will deliver 10-15 mpg if driven carefully and the motor isnt revved too high too,something to consider while your chugging up a hill at 35mph with a 250 six--and getting the same mileage.. :blush:

A 6.2 would be hard to beat in a 60-66 GM truck--or the rare 3 cylinder detroit diesel some were equipped with--those would tow any thing you want and get real good mileage doing it too...maybe a Perkins or Cummings would be even better! :laugh:
 
joez said:
Not a chevy, but still.

One of our old work trucks was a ford with a wide ration T-18 and a 300 I-6. That thing may not have been the fastest tow rig, but it towed circles arround the supposed to be replacement 2003 f-150 with a 5.4. I convinced my boss to keep that old 300 just to tow the trailer. It was down on HP, but had great low end torque.

My dad used to tow with a '69 C20 with a 292, he said it did well, but was pretty bad on fuel for being only a 6. Dont have much more information than that, he sold that before i was arround.
Click to expand...

word... furd 300's are good torqy motors... I've wheeled with a few f-150's with 35's and a 300... did pretty damn good for a six.
 
There is a reason why GM never put a 305 V-8 in a 1-Ton truck and why they DID put a 292 in a C-40/50. Like others have said you will not be the first one to get where you are going but you will get there with ease with a in-line six cylinder.
I have watched a 1978 K-30 Cab chassis Wrecker with a 292 and 4.56's get the stew worked out of it for years and not once did the owner ever complain about the motor . In fact when the motor finally went it was replaced with a GoodWrench short block 292 and saw several more years of duty before the body just about rotted of the frame.
I agree that a 350 or larger engine will make way more power but the 292 is all about the bottom end grunt and will out torque most motors at real low RPM's. A 350 does make for a fine occasional tow motor and so does a 292/250 it all depends on the driving style and intended usage.
Tom
 
Since you are particular about the 60-66 body style I would suggest a 64-66 GMC 3/4 ton with the 250 I-6. They came with leaf springs rather than coils in the rear like Chevy was selling. Plus it is alot easier to put the 73-87 3/4 ton disc brakes onto the front suspension of the 63-66 trucks than the 60-62. The 60-62 used torsion bar front suspension and can be very expensive to go disc if you want to keep the torsion bars (not so bad if you don't mind putting the 73-87 donor coils suspension on the truck instead though).

I've got a lot of experience hauling big loads across country using a '66 GMC 3/4 ton 2wd. It had a 305 V6 (yes I said V6 :grin: ), SM420, Dana 60 rear w/ 4.10 gears. I've grossed 10K+ crossing scales in Wyoming with it on the truck and trailer. Disc brakes are not required, but definitly worth having in the mountains.

I've also seen a few guys converting to 6.2L diesels in the 60-66 body style and really liking it. Pulls as strong as most I6 and 305 V6 motors but better on economy.
 
I built a 300 I6 for my old 85 Bronco .It ran great. Would run rings around 350s and other SB V8s. It had Headers, Cam, 4 barrel intake / Q-Jet, ported heads, 9.2 : 1 cr. Balanced. It towed a 55 F100 400 miles on the interstate no problem. I used to tow my boat and travel trailer all over the place with it too.
Unloaded on the highway it got 17 MPG. That was with a C6 trans 3.40 gears with no OD.
 
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