experienced advice requested for overhaul

https://www.summitracing.com/parts/nal-14097395/overview/

I have one in my 1997 and love this cam.

Ernest Alvarado said:

https://www.summitracing.com/parts/nal-14097395/overview/

I have one in my 1997 and love this cam.

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how is the idle on this cam? Any hesitation or stumble from idle to throttle? I have looked at this cam but get caught up in the "specs vs reality" game. On paper this cam should have a rough muscle car like idle because of the 109 lsa (vs 111 stock). It also shouldn't cooperate with efi computer tuning (obviously it does, but on paper...)

gibsonfarmsmo said:

how is the idle on this cam? Any hesitation or stumble from idle to throttle? I have looked at this cam but get caught up in the "specs vs reality" game. On paper this cam should have a rough muscle car like idle because of the 109 lsa (vs 111 stock). It also shouldn't cooperate with efi computer tuning (obviously it does, but on paper...)

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I have done a fair amount of vortecs and researched quite a bit on what to use and not. 109 LC cam would work in a 305 because of the small bore. In a vortec setting 350 it may work only because of the low duration at .050. I have used a 208/216 @.050, ground on a 112 LC. in a 350 you will need a 106 ILC, but retain the 112 lc. This will work with a stock computer. I have used them this way and very satisfied with the results. This cam will pull to about 5500 in a 350. Lift on this cam is .450/465 with a 1.5 rocker. You can also use LS springs and retainers to save weight. Chevrolet is the best place I've found to purchase them. Get the Z06 springs.

http://www.lunatipower.com/Product.aspx?id=1834&gid=254
This is the cam i run in my daily driver and i love it

I have a 94 suburban that was swapped to vortec engine I'm running the 395 cam ls6 springs 1.6 roller rockers 411 pcm swap 60 over pistons mpfi injectors cold air intake and headers and true dual exhaust my truck is 6500 pounds with 35" tires and 9" lift 410 gears it has alot of power and I occasionally tow cars on a car hauler that cam is very good for a daily driver and really makes that engine come alive

Gidday mate.

Don't bother comparing the LS variant to the vortec, apples vs. oranges. Engineers do know what they are doing but the bean counters (accountants) control things at the manufacturers. Long tube headers unleash hidden power, mufflers keep it quiet.


Here is some light reading:

http://www.gmt400.com/threads/350-cam-options.33150/

http://www.gmt400.com/threads/98-l31-k1500-camshaft-question.37169/


I would stroke your motor to a 383 or purchase this and re-cam it. Alot more torque and that is what we need for our trucks. Keep the LSA under 110 (narrow). It helps develop the torque earlier in the rev range. Bigger or wide LSA numbers are more suited to blown/turboed motors and higher rpm.

The 395 marine cam is one level above stock. Same idle, frees up the power, everything you are asking for in a cam.

Next step up would be this one a little more power. More cam is nice but power starts to get higher in the rpm range which would be counter productive for your needs.


If you decide to install 1.6 ratio roller rockers for more lift - Alex parts have a beehive spring kit It's a great kit and slightly cheaper than sourcing the parts individually from summit or jegs. Plan to include replacing the stock press-in studs with the threaded type rocker studs you can use the other type studs which have the hex nut but you have to machine the heads down = pain in the a$#e, when these go straight in. Be aware of the clearances, mine did not achieve the advertised .550" The valve guide boss required a little machining.


I wouldn't bother with the 411 upgrade unless you are tuning yourself or installing an LS motor. A Black Bear Performance tune will be sufficient.


Either cam will be fine for what you are asking. I would install the howards cam in the 383 and you would be around the 440hp mark. Very close to the limit of the stock fuel injection capabilities and flow of the stock heads (which is why the LS is such a popular swap, easier options to upgrade e.g. stock 5.3 is 365hp add a single turbo @ 8psi = 500+hp) Stock L31 motor with the 395 marine cam will be around 300hp. Add 1.6 rockers for around 15-20hp. HP = $$, depends how far you want to go.


Hope that helps you and happy reading.

The cylinder head architecture is completely different between the SBC and LS style motors. As such their cam timing requirements are completely different. Stock LS heads flow as good (and sometimes better) than many aftermarket SBC heads.

With that being said, stay under 210 degrees @ .050 duration on the intake side, 112 degree or higher lobe separation angle and should have a nice smooth idle with more usable power. Vortec heads flow very good at low and mid lift, stay under .450" lift and you won't need to upgrade valve springs.

Thank you to everyone that responded. from what I understand about LSA,the wider the LSA the flatter the torque curve, giving lugging power throughout the rpm range. I have it narrowed down to 2 different cams. The stock cam specs show that it is a pretty mild cam and it wouldn't take much to improve on the power of the engine. i don't want to go with too much more duration as I don't want to move up to more RPMs for power. This engine will need torque down low.

stock cam

190/195
,414in .423ex
111lsa

I'm looking at a melling

198/210 @.050
.434in .464ex
112lsa

or a crower
196/204
.464in .484ex
114lsa

I probably wouldn't be able to tell the difference between these two cams installed in the engine. I just know that they will be a decent improvement above stock. The crower would probably idle a little smoother.

I was planning rebuilding the heads while I had it apart so new springs were in order anyway. I grew up on a farm so rebuilding and tweeking engines is/was a a common task. the 0411 upgrade was planned anyway and I figure it just opens up the tuning options.

Widening the lsa reduces maximum torque. Neither of those cams have any place in a truck motor.

1BigCarrot said:

Widening the lsa reduces maximum torque. Neither of those cams have any place in a truck motor.

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How would they not? I'm not trying to argue, I just want to know why you think they would not be a good choice. Cams and components expense can add up quickly so I want to make sure I'm making a good decision.

if you look at the stock specs of the l31 you will see that those two cams have just a little more duration and lift than the factory cam. They both are very similar to the ramjet 395 cam that most recommend, only with a different LSA number. shorter duration puts power at lower rpm, like what you would want in a 5000lbs truck. most cams that are found for small blocks are in the 200 to 220 duration range and are meant for cars that weigh much less and develop their peak power at higher rpms than what are desired for a truck. while widening the LSA peak torque will go down, but not by a lot and usually only seen on a dyno stand. narrow lsa's develop torque at lower rpms, but drop off drastically after peak torque. wider LSA may develop less peak torque, but keeps it flat across the rpm range.

what makes a truck a "truck" usually isn't the engine, its the gearing in the transmission and rear end. 80s gm larger cars and trucks shared the same engine with the same internals. the cars usually had higher gearing in the tranmission and rear end than the trucks. which explains why an 80s 1/2 ton would get 10mpg but could tow a boat, and the car would get close to 20mpg but not ideal for towing anything.