5.7L Towing Upgrades (yes, another thread)

[Erik the Awful]

Good tip, thanks. I was curious about that anyway. I guess I'll use the 1.5 full roller rockers that cost $400 instead.

For a towing motor, I'd stick with the stock rockers. You already have them, so they're free. Full rollers are really only beneficial if you're revving over 5000 rpm on a regular basis. Your cam already has a lot of lift, so I wouldn't bother with 1.6:1 either.

I looked up your cam specs: 210/214 duration at .050, .474/.474 lift, 111 LSA.
Internet says stock L31 specs: 191/196 duration at .050, .414/.428 lift, 111 LSA
That's definitely going to need a tune, but you can get it running and minimally driveable on the stock tune.

Out of curiosity, did you call Comp Cams and get that recommendation, or did you pick that cam? When I bought my cam I picked one myself, then second guessed and called Lunati. The guy at Lunati talked some sense into me and I exchanged my cam for a much more suitable cam.

 

[Trenton]

For a towing motor, I'd stick with the stock rockers. You already have them, so they're free. Full rollers are really only beneficial if you're revving over 5000 rpm on a regular basis. Your cam already has a lot of lift, so I wouldn't bother with 1.6:1 either.

I looked up your cam specs: 210/214 duration at .050, .474/.474 lift, 111 LSA.
Internet says stock L31 specs: 191/196 duration at .050, .414/.428 lift, 111 LSA
That's definitely going to need a tune, but you can get it running and minimally driveable on the stock tune.

Out of curiosity, did you call Comp Cams and get that recommendation, or did you pick that cam? When I bought my cam I picked one myself, then second guessed and called Lunati. The guy at Lunati talked some sense into me and I exchanged my cam for a much more suitable cam.

The cam i was originally going to go with I found by comparing cams myself, but @L31MaxExpress suggested a better camshaft. I have lifetime free tunes from Blackbear, so I'm not worried about a tune. I planned on getting it retuned after the new mods, anyway.

 

[Supercharged111]

The lobe separation on that cam seems a little bit on the narrow side to me, and would definitely require a tune for the conputer to not throw a fit. Good news is even with the slightly higher ratio rockers, it still falls into the lift limit of the L31 head. Barely.
Springs and retainers might work? Someone probably knows better than me on that.
The headers are probably well suited to what you're going for.
Do you have 4.10s in your truck? That would be a requirement, I would suspect. If so, you're already rated at 7k towing.

The lobe separation on that cam seems a little bit on the narrow side to me, and would definitely require a tune for the conputer to not throw a fit. Good news is even with the slightly higher ratio rockers, it still falls into the lift limit of the L31 head. Barely.
Springs and retainers might work? Someone probably knows better than me on that.
The headers are probably well suited to what you're going for.
Do you have 4.10s in your truck? That would be a requirement, I would suspect. If so, you're already rated at 7k towing.

You do realize the stock cam has an LSA of 111 just like the came OP mentioned, right? The PCM has zero issue with such a meager cam. Even a TBI PCM would have no issues being tuned for that cam. Wide LSA is for emissions and eeking more RPM out of a given duration. Tighter LSA delivers more torque sooner which is what OP needs. I wouldn't get too wrapped up in the factory tow ratings, a SRW 3500 will have zero issues with the weight. If you read between the lines in the manual, you can clearly see power was the most significant factor.

 

[Dravec]

You do realize the stock cam has an LSA of 111 just like the came OP mentioned, right? The PCM has zero issue with such a meager cam. Even a TBI PCM would have no issues being tuned for that cam. Wide LSA is for emissions and eeking more RPM out of a given duration. Tighter LSA delivers more torque sooner which is what OP needs. I wouldn't get too wrapped up in the factory tow ratings, a SRW 3500 will have zero issues with the weight. If you read between the lines in the manual, you can clearly see power was the most significant factor.

Nope. Didn't realize that. For some reason I thought the stock cam was on 114 or 115 lsa. My mistake.

 

[Supercharged111]

Nope. Didn't realize that. For some reason I thought the stock cam was on 114 or 115 lsa. My mistake.

The LS stuff is mostly 116+ (and sometimes retarded), but not so for the 350 motors. Part of why they pull better up top, and also part of the reason they were able to ditch the EGR valve.

 

[Dravec]

The LS stuff is mostly 116+ (and sometimes retarded), but not so for the 350 motors. Part of why they pull better up top, and also part of the reason they were able to ditch the EGR valve.

Ah. Thanks for learning me!

 

[Hipster]

I'm not a fan of full roller rocker rockers on the street either and definitely not an aluminum one. A weekend warrior ok, but not on a long range truck toting a trailer. You can get long slotted in the standard variety in 1.5 and 1.6. When roller fulcrum let loose it spits the needle bearings through the engine and you'll be looking at a teardown and cleaning/iinspection at the minimum if they don't chew up a bunch of other stuff.

Buy a flat deck car trailer that's 2500+lbs less. Less weight , less wear and tear on the rig, less fuel on each trip, unless there is some other plan at play for buying the big trailer.

 

[L31MaxExpress]

I'm not a fan of full roller rocker rockers on the street either and definitely not an aluminum one. A weekend warrior ok, but not on a long range truck toting a trailer. You can get long slotted in the standard variety in 1.5 and 1.6. When roller fulcrum let loose it spits the needle bearings through the engine and you'll be looking at a teardown and cleaning/iinspection at the minimum if they don't chew up a bunch of other stuff.

Buy a flat deck car trailer that's 2500+lbs less. Less weight , less wear and tear on the rig, less fuel on each trip, unless there is some other plan at play for buying the big trailer.

Been running aluminum roller rockers for years on street and towing engines. Have not had one problem. Have had more problems with factory rockers. With factory rockers I would not go over about 100 lbs seat pressure, 250 open or more than 0.470 lift. Otherwise they will quickly wear out the rocker ball area and break apart. I never have bought a roller rocker arm that does not have a sealed trunion bearing.

Full roller 1.6 roller rockers will add torque everywhere in the powerband compared to standard rocker arms and the gain is fairly consistant. Roughly 10-15 ft/lbs across the whole rpm range from off-idle on. That is only a few hp down low in the rpm range and bigger gains up top but torque across the whole rpm range is what is going to get you rolling and keep you rolling uphill.

 

[Trenton]

Buy a flat deck car trailer that's 2500+lbs less. Less weight , less wear and tear on the rig, less fuel on each trip, unless there is some other plan at play for buying the big trailer.

The reason for a gooseneck is because I prefer the way they pull and handle weight. My high school shop built one and it was so much easier to maneuver. I liked the way they pulled on the highway versus a bumper pull trailer. Pulling the weight through the mountains in a 22 year old truck, just gives me piece of mind. Eventually, I want to get a diesel and turn my current '98 into an off road rig and haul it around, but that's also a dream.

It already sucks on gas, I can't imagine being any worse, lol. My daily driver gets a whole lot better in town than the '98 will EVER get on the highway unloaded, and it's what I normally drive. You don't do these things if you're worried about MPG.

 

[Supercharged111]

I'm not a fan of full roller rocker rockers on the street either and definitely not an aluminum one. A weekend warrior ok, but not on a long range truck toting a trailer. You can get long slotted in the standard variety in 1.5 and 1.6. When roller fulcrum let loose it spits the needle bearings through the engine and you'll be looking at a teardown and cleaning/iinspection at the minimum if they don't chew up a bunch of other stuff.

Buy a flat deck car trailer that's 2500+lbs less. Less weight , less wear and tear on the rig, less fuel on each trip, unless there is some other plan at play for buying the big trailer.

With a wimpy truck cam I just don't see an issue with a good aluminum full roller rocker. I went with the Comp Pro Magnums on my 1500 out of pure paranoia and they are dead silent. I do agree with the bumper pull sentiment. Yes a goose pulls nicer in some ways, but when you're under 10k it just seems like you're splitting hairs.