1983 454 vs 5.3 LS for towing

[BeefSupreme]

About a year ago I bought a 1983 C35 3+3 dually. Its currently a 454 with a 700r4. Fires right up and cruises fine on the highway, I drive it to work regularly.

Here's my issue:

I want to be able to use it to tow a 5-6000 lb trailer about an hour or so on occasion to get my tractor to and from my property. I don't trust the 700r4 to tow at all, even though it was rebuilt by a reputable shop about 2 years ago. Also, with the recent heatwave the engine has been creeping a little above the 210 mark on the temp, and that's with no load.

Im planning to 4L80 swap it to get the dependability in the towing. I have a 5.3 LS I can install at the same time, but would this be an upgrade in towing from the 454? I would imagine the day to day would be better, and certainly lighter. Any thoughts or experience is welcome.

 

[Catbox]

Has anything been done to the 454 as far as upgrades?

Mine has all the basic hot rod bolt-on's like carb, intake, headers and a small RV cam.
There is far more power on tap and it never misses a beat.
We don't rely on it as a primary but even in the heat it hasn't had any issues with getting hot.

Make sure your clutch fan is happy.

 

[BeefSupreme]

Has anything been done to the 454 as far as upgrades?

Mine has all the basic hot rod bolt-on's like carb, intake, headers and a small RV cam.
There is far more power on tap and it never misses a beat.
We don't rely on it as a primary but even in the heat it hasn't had any issues with getting hot.

Make sure your clutch fan is happy.

It has the "Performer 2.0" Intake and an AVS2 carb, but thats it afaik. I had considered a cam and headers as well.

As far as the cooling, fan seems to be in good shape, and no leaks from the rad. I may end up with a big 4 core aluminum and some e-fans, might cool better and save a little power. I guess the question still is, if I spend $1500 on all the upgrades just mentioned, am I better or worse off with the 5.3 for around the same money?

 

[SirRobyn0]

This is all a matter of taste IMO. I'd want the 454 / 700R4 combo over the 5.3 4L80 combo. Main reason I can fix or bandaid a lot of stuff on the 454 I couldn't with the 5.3's electronics. I'd be far more worried about what ratio is in the rear end, (and the fan clutch & the radiator) than any kind of swap.

FYI @BeefSupreme I run a 1984 C20 305 / 700R4 and tow loads like that in our hill areas just fine. The truck does great it's just not the fastest.

 

[BeefSupreme]

This is all a matter of taste IMO. I'd want the 454 / 700R4 combo over the 5.3 4L80 combo. Main reason I can fix or bandaid a lot of stuff on the 454 I couldn't with the 5.3's electronics. I'd be far more worried about what ratio is in the rear end, (and the fan clutch & the radiator) than any kind of swap.

FYI @BeefSupreme I run a 1984 C20 305 / 700R4 and tow loads like that in our hill areas just fine. The truck does great it's just not the fastest.

Thanks, thats good to know. Its a Dana 70, 4.10 gears. With the 700 its about 65 on the highway at 2k rpms.

I will definitely be looking into the cooling system in the short term no matter what. It runs at normal temp all the time, til its over 100 outside. Not sure there is any good way to keep the BB cool when its that hot honestly.

 

[HotWheelsBurban]

The 454 with the 4L80E and a full floating 14 bolt rear axle oughta tow just about anything that the frame and suspension can handle.

 

[SirRobyn0]

Thanks, thats good to know. Its a Dana 70, 4.10 gears. With the 700 its about 65 on the highway at 2k rpms.

I will definitely be looking into the cooling system in the short term no matter what. It runs at normal temp all the time, til its over 100 outside. Not sure there is any good way to keep the BB cool when its that hot honestly.

Keep in mind when these trucks were new they were designed to function properly in various weather. If your running a 195 thermostat, that is the temp the thermostat begins to open. It's probably fully open at 205 - 210. Fan clutches generally kick in to keep the engine under 220. A modern vehicle with electric fans nearly all the manufactures program the fans to kick on at 220.

I think seeing 220 at 100F is normal. check the fan clutch, make sure the radiator isn't full of calcification, and if you really want to try a 180 stat.

 

[Catbox]

The 454 with the 4L80E and a full floating 14 bolt rear axle oughta tow just about anything that the frame and suspension can handle.

This will be the route that I take with my truck.
I will be eventually replacing the SM465 with a 4L80 I have in the stock pile of parts.
That transmission with the big block should be about unstoppable.

I do have the matching 454 from the 1997 truck that the trans came from that will also be going in at the same time the trans will be. Then I will have a roller cam engine too.

 

[Catbox]

It has the "Performer 2.0" Intake and an AVS2 carb, but thats it afaik. I had considered a cam and headers as well.

As far as the cooling, fan seems to be in good shape, and no leaks from the rad. I may end up with a big 4 core aluminum and some e-fans, might cool better and save a little power. I guess the question still is, if I spend $1500 on all the upgrades just mentioned, am I better or worse off with the 5.3 for around the same money?

That Performer intake is the same one that we have on our truck.
It really woke the package up as far as more power everywhere.

I would definitely put a set of headers on it to allow it to breathe easier.
My engine came nearly stock with just the little cam in it from when it was rebuilt.
We changed the carb from the worn out Quadrajet to a Holley 750, the stock intake to the Performer, and then added a set of headers from a 1968-72 Nova.

It is way more fun to drive now and I am sure if I kept my foot out of it I would be able to get 12 or so MPG.
But I like the way it sounds....

 

[82TwoHeadlight]

The 454 is a much better option for towing than the 5.3. It makes a ton more torque and torque where you need it. I'd use the 700r4 too because it has a very low (high numeric) 1st gear ratio that makes it much easier to accelerate from a stop when towing a heavy trailer.
You mentioned potentially going to electric fans. Do NOT do this. A mechanical fan with a functioning fan clutch will pull far more air than any single or dual electric fan setup can and has fewer points of failure. If you're concerned about cooling follow advice from @SirRobyn0 and check the radiator is working properly.
You might consider switching to a 160 degree thermostat if it's running something higher. Check the fan clutch for play by grabbing on blade of the fan (while it's not running) and try to wiggle the fan front and back relative to the truck. There shouldn't be any play in it.
If you want more power and mileage i would reiterate what others above have said, long tube headers and a performer or performer rpm air gap will help even a stock 454.

I would really discourage a 5.3 swap for your application. It's an apples to oranges comparison and the 454 is the better of the two options for towing with a 3+3 by a long shot.

 

[GTX63]

The 454 would be my choice based on power and simplicity. That doesn't mean you shouldn't do the 5.3, it just means I probably wouldn't.
There are also very few overdrive transmissions that I pull over 5k loads with in overdrive. I meant to say zero.
But I'm in Tennessee.

 

[BeefSupreme]

Thanks all, I think it makes sense to ensure the cooling systems is in good shape, I think Ill start there. If it cools off a bit ill do a test run locally with the trailer.

Im also thinking adding a trans temp gauge would be a good idea. Anyone have expenience with the trans coolers that have their own little fan?

 

[fast 99]

Our company had several tow trucks with automatics. Both 350 and 400 behind big and small blocks. Heat is the number 1 tranny killer. I used 1-2 additional large tranny coolers in series with cooler in radiator.

Just for my personal information put a temp gauge on 1 truck. On the flat temp stayed in the 150-range towing 3-4k with 3.73 gears 65mph. On grades temp would spike over 200 rather fast. Usually got out of the throttle when it exceeded 225+. Unless something broke lifespan was around 100k. Didn't want to add more complexity with an aux fan but it wasn't necessary either. Those temps were within a reasonable range.

A local tranny shop modified an AC condenser into a tranny cooler on his personal tow vehicle. Said he never had cooling issues.

 

[Keith Seymore]

The 454 is a much better option for towing than the 5.3. It makes a ton more torque and torque where you need it. I'd use the 700r4 too because it has a very low (high numeric) 1st gear ratio that makes it much easier to accelerate from a stop when towing a heavy trailer.
You mentioned potentially going to electric fans. Do NOT do this. A mechanical fan with a functioning fan clutch will pull far more air than any single or dual electric fan setup can and has fewer points of failure. If you're concerned about cooling follow advice from @SirRobyn0 and check the radiator is working properly.
You might consider switching to a 160 degree thermostat if it's running something higher. Check the fan clutch for play by grabbing on blade of the fan (while it's not running) and try to wiggle the fan front and back relative to the truck. There shouldn't be any play in it.
If you want more power and mileage i would reiterate what others above have said, long tube headers and a performer or performer rpm air gap will help even a stock 454.

I would really discourage a 5.3 swap for your application. It's an apples to oranges comparison and the 454 is the better of the two options for towing with a 3+3 by a long shot.

This.

K

 

[Keith Seymore]

Check the fan clutch for play by grabbing on blade of the fan (while it's not running)

HA!

K