Towing with my '74 C-10

[egleaves]

Hey all....I'm new here and looking for opinions (or facts if you got 'em) about putting a crate motor in my 74 C-10 Cheyenne.

I've only had the truck a few weeks, so we're still getting to know each other.  I pulled my 30' camper a couple of hours down the road for Memorial Day weekend with no issue....except that the rig doesn't care much for hills and the drive home was against an exceptionally strong head wind.  I couldn't get it over 50 mph in that wind.  It feels to me like I need more torque.

I already know that what I am towing is near the threshold of what the truck is rated for, but it does have beefed up rear springs (RPO 1G50) and I don't tow far/often....yet.  I want to spend more time out with the camper, and I want to pull it with this gorgeous truck, so I'm contemplating a torque/HP boost from a crate motor.

One of my big concerns is that I might snap the cam or crank in this 40 year old engine.  Or burn up a piston.

My research so far has shown that I'll be lucky to spend anything less than $2K on this operation.  I'm always a little wary of the "cheapest" option....I believe you usually get what you pay for . 

Is is worth the extra money to spend as much as $3K on the right setup?  I'm going camping, not racing.

Is my engine stout enough to simply bolt on some extra torque?  I can swap a cam or a head and I can change an intake system, but I'm not equipped or experienced enough to mess with cranks and pistons.

[LTZ C20]

Welcome from California. Nice truck and trailer! I have a 30 footer myself, no slide outs tho.

[zieg85]

Welcome BTW.  If the GCVW is within range it maybe that you need a little lower rear end gear to make it work.  You need to access your engines health first to figure out which direction to head.  What engine, Trans, and rear end do you currently have?  Trailer brakes? Sway control? Weight distributing hitch.  LT C rated tires?  These are all safety concerns to have.

[Car10s]

If I were in that dilemma I would just find a 6.0 engine

[VileZambonie]

Welcome BTW.  If the GCVW is within range it maybe that you need a little lower rear end gear to make it work.  You need to access your engines health first to figure out which direction to head.  What engine, Trans, and rear end do you currently have?  Trailer brakes? Sway control? Weight distributing hitch.  LT C rated tires?  These are all safety concerns to have.

This

Can't offer much help without knowing what you're starting with

[egleaves]

Basic stats are in my sig, but I'll rehash and expand.

350 ci
TH400 3 speed auto (unconfirmed)
3.73 rear end (unconfirmed, but pretty sure)
Accelerometer based progressive brake controller
Electric trailer brakes
Weight distributing hitch with sway control
I'd have to check on the tire rating, but they are brand new

Towing stability has been excellent...even in high wind. I just need some more oomph.

[zieg85]

Basic stats are in my sig, but I'll rehash and expand.

350 ci
TH400 3 speed auto (unconfirmed)
3.73 rear end (unconfirmed, but pretty sure)
Accelerometer based progressive brake controller
Electric trailer brakes
Weight distributing hitch with sway control
I'd have to check on the tire rating, but they are brand new

Towing stability has been excellent...even in high wind. I just need some more oomph.

If you are having trouble with that setup, you either have timing issues, a wrong cam choice by previous owner, or your engine is real tired.  In stock form you should have zero problem pulling that trailer IMO.  I would start by confirming your rear end gear.  A 2.56 or 2.76 gear would be a dog but a 3.73 should have no issues at all

[egleaves]

I've been a bit suspicious of the timing, but haven't had an opportunity to check it.

....forgot to mention the GVWR of the trailer is 6900 lbs.  Truck weighs 5000 lbs with a full tank of gas and two meat sacks up front (just had it on a scale this morning).

When looking for towing capacity I found this chart (see image), but it's for the second gen trucks.  Would these numbers still be the same for third gen?  According to this chart I should only be hauling 4500 lbs with the truck.  This math is not working out in my favor.

[egleaves]

Whoops....I hit the post button before I attached the image. 

[Jason S]

From your description, it sounds like it's an original '74. Does the engine still have the points distributor?

[egleaves]

From your description, it sounds like it's an original '74. Does the engine still have the points distributor?

Not sure, but I can check on that tonight.  Think I might just need new points, or better yet, an EI conversion? 

[Jason S]

Not sure, but I can check on that tonight.  Think I might just need new points, or better yet, an EI conversion? 

If it still has a points distributor, upgrading to HEI would be a good thing.

[roundhouse]

Confirm the axle ratio
A lot of trucks had 2.73 

Have the compression and timing checked
It should pull ok unless you have low compression from a worn out engine

Make sure you have a very large high quality auxiliary transmission cooler and maybe a trans temp gauge in the pan
 


Sent from my iPhone using Tapatalk

[74k20]

Here might be some comparison info.  I inherited my grandpa’s ’74 k20 that he bought new (stock 350/th350/4:10 gearing).  Still had the original untouched motor.  It REALLY sucked with very low towing power (drank a LOT of fuel also as I had to keep my foot into the QJ).  It still ran real smooth and quiet for 155k miles and didn’t even burn oil, but it felt tired.  My 2000 Honda Passport 205 V6 (195k miles) towed nicer than the big truck power wise.  I was soooooo slow up hills pulling a simple quad trailer.  Original points distributor and probably worn out carb on original intake and exhaust manifolds to dual exhaust, th350 trans.  Basically all stock except for the small dia dual exhaust.  I never fine-tuned the motor, as goal was to replace anyway.

So I pulled the smooth running tired weak HP motor out last year and replaced with a fresh mild built sb400 that ended up only lasting 1 week (shop installed wrong pistons and WAY too high of CR).  Instead of re-installing the original motor back in, I had a low mile 260hp crate motor sitting in my garage.  The crate motor has a mild summit CAR type cam, edelbrock performer intake, HEI, and the new sb400 intended QJ carb from SMI (bit to big).  Also now has long tube headers and larger dia dual exhaust.

Yea long story – whoops.  Point being, I’m NOT really that impressed with the 260hp crate performance in the heavy truck, as it’s currently set up.  But that’s the problem…..I’ve got a mild low tech CAR type cam as I planned on putting this motor in the wife’s ’68 Camaro as a mild/dependable driver – NOT intended for a heavy 4x4 truck.  However this motor still does MUCH better than the original motor once I get some RPM’s up a little higher.  My new replacement SB400 is about done, so the crate motor will be coming back out.  If for some reason this motor ends up back in the truck, I WILL BE installing a low grunt Comp Cam.

74k20

[Stewart G Griffin]

The Gear ratio should be on your SPID sticker.

Gearing is really the key here.  i tried towing a chevette and open 16' car trailer with 2.56 gears.    You can't.

Truck really struggled up hills and had difficulty maintaining 65mph.