a friend of mine has a 96 silverado, and is looking for a cam for it but coming up short... i have been searching around for options and info i am getting kinda discouraged. we are in California and it needs to pass smog no problems, and i was hoping that we wouldn't have to change out valve springs, but if it had to be done, so be it. but the problem is the more i read the more i see that the intake/injection system is no good for modding on these engines.

can someone shed some light on the fuel injection system, its limits/how big of a cam it could handle and what its tunability is and maybe what the max lift on the stock springs are?

any help would be appreciated
-anthony

 

I am doing the same exact thing. my cam decided it was time to not be nice and misfire and intake on 5 don't wanna open fully so i was looking at cams without having to do any more head work. luckily i called lunati, comp cams wouldn't take me off hold. lunati rep. told me about this Lil cam. 54760-LUN. it is basically a just a little over stock cam. i am still doing research on it, the guy said i can use everything stock. so the same rockers and pushrods and so on. lunati has some other cams with slight less lift but different duration but also may require computer tunes. i had planned on doing a tune along with my long tube headers but being that i havnt driven it in 1.5 months from me tryin to figure what isnt opening all the way, i found the issue. but try looking at lunati. thats the stick i plan to toss into my block and see if wants to stop misfiring and act right so i can finish throwing the long tubes and hydroboost on.

 

i believe stock cam is a 194/197 @ .050 with 4.150/4.2 lift

that cam (lunati 54760lun) is 213/219 @ .050 with .447/.471

it seems quite a bit bigger to be considered 1 step over stock, but i will check out lunati's stuff

so do you know what the max lift on the stock springs is? how big of a cam are you running? any problems with the fuel injection system being able to handle it? what do you use to tune it?

 

stock cam according to the haynes manual is .276 intake lobe .285 exhaust and with stock valvetrain total lift calculated with 1.52 rockers comes to .41952 intake and .4332 exhaust. i have come to the conclussion that stocker springs are good for .480 lift. after that its time to swap to beehives or ls2 springs. as ive researched, the stocker fuel is good for 300 wheel horses. the lt4 hotcam has been recommended, but where it makes real power the stocker intake chokes it and you have to swap out springs and i hear some even machine the guides down to get proper lift with 1.6 rockers. i called lunati direct and the first cam he said that was mild is the one i said. i asked if any spring swap or machining is needed he said no, I will be calling once more to get a much more detailed description and to triple check that all i need to do is pull the old stick and push the new one in. also, gotta see if i need to give the cam any degree or stay stock and keep it at 0 degree. i told the guy i was looking for something just over stock, i have long tube headers going on, and everything else stock. thats what he said to use. so, it will still work, I do not plan to add 1.6 rockers on, i plan to only put the cam in hope to the engine gods my misfire is gone and it runs true again, then swap to roller tip rockers later on. ill post what the next call reports. hope this helped. hell, theres always the custom grind cam lol.

 

thats cool, thanks for the info, my friend is trying to get to 350~ horse, he has a flowmaster exhaust system(he likes the sound even tho i have told him about magnaflow) and k&n intake and is looking for a little more, he is thinking about shorty smog legal headers as his next move and then a cam a lil later, he's been lookin around and so have i, and while the shortys arent an improvement on the ls style engines they seem to be an improvement over the older 350 manifolds so hes wanting to give them a shot, he was looking at a T.B. spacer and i discouraged him from that seeing as the only time i have seen a gain is when air and fuel go thru it so he was looking for something else, he doesnt want something that requires any extra care, stock type maintenance, no lope and no loss of low end, as he uses it very much for a truck, i was thinking a cam somewhere in the 206,212 range with around 460~ish lift on a 114+ to keep the comp happy but i wasnt sure of the fuel injection systems capabilities, hes on a tight budget so it needs to be a for sure that the thing will work, thats why i posted here, i have been on here a while and you guys are some of the most well educated via hard data and trial and error that i have seen.

 

Stock springs are good to .450 lift and the push in studs are good to .475 lift. The Lunati cam is a good upgrade with the stock stall and 3.42 or 3.73 gears whichever your buddy has from the factory if he hasn't replaced them. The Lunati that was recommend is a good choice for just a spring change. If he is interested in a bit of head work, the Crower 214/220 would be a good choice and has .53x lift as well. The vortec heads in stock form peak in cfm around .450 but with some porting, they can flow really well.

You'll need to get tuning obviously. Also, have you removed the baffle on the butterfly (in the throttle body) for more cfm?

Check your exhaust tubing as well. The head pipes (pipes between the manifolds and cats) are 1 7/8" which need to be bigger as well.

Do not do a throttle body spacer...it does nothing. Spend the money on headers, exhaust, e-fans, or ignition system.

 

ok good advice there, i will try to talk him into having the head pipes redone and going to a magnaflow, and i didnt even think about the efans, is there a bolt in kit for it or is that a custom deal? and what can/should be done with the electrical system?

another question is will that lunati cam lope? and what do you guys use to tune those trucks?

 

HPT doesn't do the 96 or 97 Silverados but I know tunercats can be used on those years. Otherwise, a mail order is needed.

Flex-a-lite has a kit ready to rock and roll for those trucks for e-fans. Might need a piece or two in metal done but nothing a L piece of tubing can't do.

As far as ignition, you can do the Big 3 to help with the amperage draw and look up DUI ignitions for a complete Vortec kit..new module, coil, wires, etc.

The Lunati cam is tame but will have a hint of lope to it...nothing special. The Crower on the other hand has more aggressive lobes and will have a noticeable idle. Should pass Smog without issues given that the Crower is on a 114 lsa and the Lunati is on a 112 if I remember correctly. Crower will need screw in studs though so more head work so probably if you just want a spring swap, the Lunati would be a better choice. You can also do roller rockers as well to help... 1.5 or 1.52s would be fine but 1.6s would get you in the range of screw in studs with the Lunati cam.

 

You can use Jet DST or TunerCat’s if you can find someone who wants to unload it, as TunerCat’s is no longer available to the public.