L98, Vortec heads, lt4 cam question..
 

hey fellas, I've used the search bar pretty extensively and have not come up with a solid answer to a few questions I have.. here's what I have.. stock l98, scoggin dickey tpi base manifold and a set of brand new vortec heads.. I'll be installing the heads in the spring but while I was in there I'm seriously considering a cam.. I've read the lt4 cam is a nice cam choice for the tpi setup and I'd like to install one.. I've read about adding 1.6 rockers to be compatible with the new vortec heads but I can't find anything about what valve springs I'd need if any.. are the stock vortec valve springs good enough to run with the lt4 cam? Also, should I decide not to run a aftermarket cam shaft, will the stock vortec rockers work fine with the stock l98 cam? Any help is appreciated. Thanks

Re: L98, Vortec heads, lt4 cam question..
 

There's nothing about the stock L98 cam that will cause problems with stock valve springs. Where you'll run into trouble is switching to a cam with more lift. Specifically the problem is that nearly all OE cylinder heads will only allow so much lift before the valve retainer hits the valve seal. Beyond that, stock springs generally aren't matched well to aftermarket cams, which means upgrading the springs. Aftermarket springs may require additional machine work before they'll fit the heads.

Get on the Google and search for "valve lift vortec" and start reading. Tons of different solutions out there.

Re: L98, Vortec heads, lt4 cam question..
 

a set of stock vortec's or a set of scoggin dickey vortec's good for 550 lift?
LT4 hotcam will need better springs no doubt. I think stock seat pressure is 80lbs which isnt nearly enough for a roller cam. You may also need to clearance the pushrod holes while your in there if your doing 1.6 RR's. Also while their off you might want to do screw in studs.

Re: L98, Vortec heads, lt4 cam question..
 

I just have a regular set of vortec heads, the manifold itself is the SD. I'm really not sure what cam to go with.. I've searched and another good cam seems to be the crane 2032.. I'm wondering if I'd need springs and rockers for the vortec heads to work with the 2032??

Re: L98, Vortec heads, lt4 cam question..
 

Not sure what cam would be the best for you. I always go for something with the most torque but if you're doing cam and springs I would suggest getting threaded rocker studs installed while the heads are off.

Re: L98, Vortec heads, lt4 cam question..
 

Thanks for the reply guys, maybe I'll start a thread over on the TPI page to see what cams are generally the best to run in the l98

Re: L98, Vortec heads, lt4 cam question..
 

There are lots of things to consider when choosing a cam, but valve springs shouldn't be one of them.....meaning, match the springs to the cam, not the other way around.

I used a zz4 cam for 10 years and loved it. I brought my stock heads to my local machine shop and said, this is the cam/specs, please set up these heads to work. It was VERY affordable. Maybe $250 to clean (mine weren't new) valve job, install screw in studs, and the necessary springs.

I think the zz4 cam was about right for a relatively stock TPI. Look at the zz9 or Lingenfelter 211and 213 for just a hair more. ...the Hotcam is a little bigger than I'd go. The Vortec heads start losing their magic over .500" lift, and the duration on the HC is smidge much for a stock TPI intake. 220*@.050 degrees of duration seems to be the generic max number for relatively stock TPIs.

Also keep in mind that while all those cams mentioned have good specs, they're all old cam lobe designs. If you have the money, pick up a new cam with modern lobes, but with the desired specs. Lunati, Comp, and everyone else will have modern cams with similar specs to all of those. ...and if they don't, they'll grind you one with little to no additional cost.

BTW-Jersey Shore? Where? I practically grew up on Point Pleasant! The 80's were a good time to be a kid up in Jersey!:thumbsup::driving:

Re: L98, Vortec heads, lt4 cam question..
 

Thanks for all that information, I appreciate it. I'll look into the zz4 cam and see what I like. I understand matching the springs to the cam and that was one of my questions.. I'll give it look..

pt pleasan?? That's a stones throw away from where I grew up in Toms River. I moved about 15 mins away to bayville but still in the area. Small world. Thanks again

Re: L98, Vortec heads, lt4 cam question..
 

one more thing to keep in mind with a cam... I'm really going for pure sound. I have some other cars that are built for speed and if I want to go fast I have them to drive. The iroc just has to look good and sound good. id like a nice chuggy cam in there but I also want to keep the tpi and not have to go through a lot of tuning. so that's why I'm leaning towards cam like the lt4, crane 2032 etc..... I just need a little advice on what cam will accomplish what I'm going for..

Re: L98, Vortec heads, lt4 cam question..
 

On my car,you could tell there was a cam (zz4), but it certainly didn't have a lopey sound. ....I have another friend with the Hotcam, and it definitely had a little lope to it. If that's your goal, the Hotcam will be just fine. It'll run well, just maybe a little overkill. ....it'll need tuning though. The zz4 cam (on an 89 MAF system) didn't even need tuning to pass NC emissions years ago. Doesn't mean a tune won't help, but it ran real well.

Re: L98, Vortec heads, lt4 cam question..
 

good info and thanks for the reply. I don't mind a little overkill. There's plenty of videos out there of both the zz4 and the hot cam to get a better idea of how each will sound. I think a lot of it depends on the exhaust. right now I'm leaning towards the hot cam kit, my car has 3'' exhaust from the y pipe back and it passes through a single 3'' bullet muffler which barely does a thing, so it sounds good and will help accentuate any cam I install.. if anyone has any other advice on the subject id like to hear it.

Re: L98, Vortec heads, lt4 cam question..
 

I run a hotcam on a TBI setup with Vortec heads and love it. The upper RPMs will not be optimal without upgrading the intake / runners with TPI but it gives you space for future upgrades. It will lope and you will hear it. A slightly smaller cam would be better optimized for your setup but not much room for upgrading intakes down the road. You can use a set of LS3 valve springs and Comp 787-16 retainers to get the lift clearance you need for the hotcam with 1.5 rockers.

Re: L98, Vortec heads, lt4 cam question..
 

If you want a little more torque under the curve and to maximize your existing setup consider something like the xr264hr-12.

Re: L98, Vortec heads, lt4 cam question..
 

The lt4 cam is a great choice with vortec heads. I just tuned a speed density one that was running 24#hr injectors and should be running 27#hr.
Running alittle lean but still a great performer.

Re: L98, Vortec heads, lt4 cam question..
 

Those two cams will have a pretty tame idle
May need something with more overlap/tight lsa youll need to tune it though
Plenty of those on the cheap out there.