tech@WS6store

iTrader: (2)

Oh yes. Very big difference.

Tuskyz28

I been digging and digging this weekend and I found something very very interesting. Stroking a 5.3 to 383 improved torque production by almost 100 lb-ft at 3,000 rpm.

Darth_V8r

iTrader: (4)

With these sorts of things, I try to keep the holy triangle of hot rodding in mind. You have performance, dependability, and cost. Pick the two that matter and sacrifice the third one. You can make power cheap, but it won't be very dependable. You can make dependability cheap, but it won't have much power. You can make great power dependable, but it will cost you.

So, once I've decided that I want to daily drive a performance built engine, i've pretty much decided it's going to cost. usually, it's not so much in the upgrades, but the supporting hardware.

For example, you can get a cam pretty cheap, but the lifters, pushrods, springs, rockers can quickly make your $350 cam a $1500 upgrade. Hell, you could go all out on $750 johnson lifters, $2K on jesel rockers, titanium hardware, etc, etc.

But anyway, back to the 6.0...

if i'm going to upgrade for efficiency -- say change to 243 heads and maybe a better cam -- i'd go ahead and do a good set of lifters like morel drop ins for $350. Might even pay for the axle oiling upgrade. Because once you decide you're going to upgrade the cam and springs, you run the risk of collapsing lifters. Small risk, but expensive if it happens (mainly due to having to take it apart again to replace it). PSI 1511 springs, 5/16 or even 11/32 pushrods, a rocker upgrade - whether it's trunions or jumping to YT or equivalent. Then I'd have no hesitation running a 625 lift cam on shorter durations and really get some torque out of it. Then it's set to run for the next 150K+ miles.

There is the added benefit that the YT or other roller tips offer over stock rockers... The progressive lift ratio of the stock rockers. Off the seat, you're closer to 1.4-1.5 lift ratio. The roller tips will get you much closer to a consistent 1.7, which translates into tip in throttle response and low to mid range torque.

AnotherWs6

iTrader: (17)

Lol, yeah, that's a bit much for truck. Maybe not the motor, but ouch, that's pushing it pretty far.

Darth_V8r

iTrader: (4)

Yes it will. But that's stroke AND bore, not just stroke, right? Kind of a general thing, but I tend to find when stroke>bore, it's great for low to mid range torque, and when bore>stroke, it's great for top end power.

Edit - I know this is the sort of thing that will sometimes get said to jar you, but being serious -- a set of TFS 220 on a 383 with a smaller cam would be a great truck engine and likely very efficient. And fixed the bore>stroke thing. Good catch, SoFla!

Tuskyz28

Yes Darth bore and stroke. A 212 duration cam in a 383ci LS will exceed 450 ft lbs at 3200 rpm with 317 heads and a factory truck intake. Not sure how much bone stock 243 heads would increase that.

Speaking on the rocker arms/cam situation. I see no need to run a 600 lift cam in a motor that's go spend hours on the highway towing. More lift doesn't always promise horsepower and torque. Brian Tooley told me that 2 years. So I would personally run straub trunions with LS6/LS3 springs with a cam no higher than 540 on the lift with some beefy pushrods and the quietest lifters I can afford. I'm thinking with a mild cam even LS7 lifters will be quiet year round with good oil. I may be wrong but that's what I'm thinking.

SoFla01SSLookinstok

I built me a tow truck engine. Something must be very wrong. Makes more HP than TQ & revs over 7k rpm. Only a 23x/23x cam w/ 5* of overlap. Odd.

Darth, you put in the same stroke>bore on both sides. You are right. More stroke helps TQ w/ piston speed. More bore is better for HP with more area. Put very simply.

Tuskyz28

What cubic inch motor did you built for towing? What intake?

My rule of thumb is on cams for what im sure some will disagree is this. When i hear 230s I think strong MIDRANGE power. I think 230s cam is too big for a motor built for towing duty.

SoFla01SSLookinstok

Lol. I have a 383 w/ fast 92 intake.

It really wasn't built for a tow truck, it's in my camaro, but Hiho started calling it a tow truck motor for some reason. Lol.

No disrespect intended Tusky.

Tuskyz28

I remember that now.
Seem like you and hio had dissagrements.

tech@WS6store

iTrader: (2)

Their small bore 205s would maybe be a better option for port velocity but keeping the powerband in check. Or 215s. Both are cnc of course so more $$ but a great option not often looked at.
The newer dart 205s are an option also.

tech@WS6store

iTrader: (2)

Id never recommend our high lift asa cam in a towing app and its not even a 230 intake and cut narrow.
Low 220s max in my experience both on customer builds and my own.

Aa far as the my truck goes, it pulled it just fine. The nv4500 is tough and the 1st gear is great. I changed the fluid a year after that and it showed no metallic issues also. Ive pulled loads heavier but not as far. Ive got another pic hauling 18k lbs of steel. That was a 7 hour trip one way. same truck 1 yr afte the wheel loader trip. I can post it for science if you guys want.

Honestly swapping to the 243s on my other truck feels like going backwards. Im constantly fighting fuel quality and knock when towing quite a bit. The 317s had no issues and it felt like I had a bit better on tap. Unloaded of course the 243s scream and get me going, but under a load, the larger chambered head seemed to win.
On a 6.0 towing app id prob send the 317s to wcch and flat mill, use a flat top lq9 piston and be better off. This is my experience from years of towing and diff engines and transmissions.

tech@WS6store

iTrader: (2)

Treat it like a boat motor. The extreme marine high lift and subsequent HUC are very popular lobes and they have over .600 lift on nearly all the lobes.
Ive seen many engines on irrigation pivots run a bigger pump at a deeper depth more easily with a higher lift cam all other things being relatively the same. Both old school bbc/sbc and with ls and the 8.1l engines as well. Both spend tons more time in the mid range with a load in them vs any street engine. They dont run high cr though. Like i said, sometimes adding cr isnt the best way to start a build.

Mos of Tooleys cams are over .600 lift. Not the truck cams but they are also low to use ls6 springs.
Looking at the tsp cam dynos i would say what he said isnt true. Going from .550 to .600 lift gained quite a bit on every cam from stg2 to stg4 then on their car cams also. They use .600 lift on any of their vvt cams and tooley uses higher than .600 also.
You should not be scared of lift to a certain point.

NAVYBLUE210

Good combo Darth, you and I are splitting hairs on the lift, lot more gain
From tusky's .540" to my .595" then from my .595 to your .625"
The 5.3-383" with TFS 220 as cast out of the box, truck Intake (maybe TBSS)
212/218, Texas Speed factory style RR with trunion upgrade, springs & lifters
You suggested 11/32 PR 10.0-10.5 Comp. 9.5:1 for regular.

Excellent low end & mid range torque, Very Fuel Efficiency under cruise.
150K+ Miles dead nuts reliability 6-8+ Hours/Day.

Tuskyz28

Reason I say 540 lift is because you don't need high dollar valvesprings to get away with a nice combo. Texas speed did a back to back test on 5.3 with the same exact duration cam. One was low lift(550) and the other one was (600) high lift. The high lift version made only 10 hp more over the low lift version. In a motor for this application I'll take less lift with increase reliability and buy cheaper valvesprings while im at it.

tech@WS6store

iTrader: (2)

Pac1218 arent expensive at all.
Plus you cannot focus on peak hp when youll never really be there in a towing app. Why even look.at hp at all? You need to look at torque. Not just peak vs peak either. Avg as well. It would be much better to see a chasis dyno comparo as the engine dyno graphs are showing as true as they should or at least an overlay. Their high lift cam only changed the max hp rpm because it pulled longer. It didnt change the rpm of the peak torque. That's what you can expect a change in lift to do really. It carried both out farther and peak hp longer but peaked at same rpm for tq.

Is there a reliability diff between .550 and .600 lift? Id say no.

The only difference is the cheap ls6 spring vs the better pac1218 or comparable spring in that price range. Gaining 10hp for only $60 more...where else will you find that?

Tuskyz28

I disagree and I'll tell you why. It's a thread on here where Texas speed had the test back to back on 5.3 motor. Cam #1 was 212/218 on a 550/550 lift vs cam #2 which was 212/218 on a 600/600 lift. Both cams was on the exact lobe separation as well. They posted the graphs on each cam. The lower lift cam looked just like higher lift cam in the torque department. Both cams had the same pattern on torque. No diifferances there. Main differences was at peak and it was peak horsepower not torque.
I also thought the lobe separation angle determines how far the rpm band carries out.

NAVYBLUE210

I would bet the 4.0" stroke with the 383" would show a more
Significant difference with the higher lift cam torque wise
From 1500-3500 RPM.

tech@WS6store

iTrader: (2)

I have those graphs. Im pretty sure i posted them also (maybe they were stg3 dynos). And i also explained the issues there as well. Did you notice the odd bump in tq then back down? Thats either from tuning or the water brake causing an issue. The high lift did pick up tq as well...but you are conentrating on 1 rpm. That is why i said a chassis dyno would be better to compare. You would not have issues with the brake etc. There is some room in the tuning as well. Ive said all of this before. It picked up a little peak torque as well. That's the stg2 212/218 im talking about.
Its also using their 100mm maf setup. Most trucks will stick to the 85mm stocker.

Lsa i not the only spec that determines how far a cam carries. The long and short of that is whenever the camshaft cannot supply the engine with the air it needs. Thats related to nearly every cam spec. Duration as well as lsa and valve events with the icl coming in to play also. And lift. Lsa can make a broader powerband but it may not be as high peak vs peak as a narrower lsa. If you look at the peak of the stg 2 it gains 100 rpm from low lift to high lift for peak. Gained 200 rpm on the stg3.

tech@WS6store

iTrader: (2)

True there