AZZ28

(Sorry it’s a little long) This is a general question, I know there is no definite answer but I would simply like to here back from someone who has experience with this set up.

Anyways, I am currently an engineering student at ASU, until I graduate I will not have the time, money, or ability to really build my '90 IROC to the extent I would like. Consequently after a few mods I decided from then on I would only add parts I knew I would want to retain on the final car, like my Koni shocks and some other stuff. Along those lines I also decided not to touch the motor since the final one will share no major parts.

Lately however I was considering installing a cam. I figure they are relatively cheap, my valves seals are somewhat worn out, it wouldn't hurt to replace the springs, and I am going to be driving that L98 for at least another couple years.

FINALLY MY QUESTION: Assuming I do the research and choose the most absolutely appropriate grind that would fully utilize the stock top end, what kind of results could I expect? I know the heads runners and base are all very limiting. I would greatly appreciate some insight into how much THE CAM ALONE would improve the power band. I would not swap any other top end parts simply because of cost. I would also not what to re-tune the prom for the same reason. Thanks in advance for any opinions/knowledge you can offer.

Current set up 1990 IROC Z (stock L98, speed density): Hooker shorties and 3" Y-pipe, magnaflow cat, SLP cat back, crank pulley, AFPR, K&N, Accel wires Bocsh plugs, fresh 700-R4

Shagwell

you'll see a good improvement. look for something like a comp 264HR(not exact pn) - would work well w/o any other major mods, and be fairly optimal for stock top end. - if you have any resources, you really should look into some minor port work on you intake while you have it off. It'll all be worth it.

Orr89RocZ

iTrader: (20)

on a totally stock TPI car, and for really cheap yet works really good, try picking up a ZZ4 cam. your gonna need springs to handle the .510 lift but it should make some good power gains.

the stock cam is weak, and little lift. zz4 is a step above and gets the lift numbers up to allow more airflow. and plus its a 208/221 cam, with a large duration split from intake to exhaust, which will help out the poor exhaust port on the stock heads.

and the added bonus is, with a AFPR, it will work well with stock ECM and chip, especially on MAF cars as they take well to bolt on mods better than Speed density. not sure how well SD will handle a mild cam, but i dont see why it shouldnt

my estimates is that you'll see 25hp with the cam alone. add a few more ponies with a exhaust system and headers. exhaust and headers on my 89 350 TPI puts me at 100mph traps and high 13's with a 2800 stall converter on street tires

91Z28-350

The ZZ4 cam will be too much lift on stock heads. You will have issues with studs pulling out and clearance for that much lift. Look at the Comp Cams XR264HR-12 cam or the LPE74216 cam. There are a ton of cams in that ballpark from a bunch of manufacturers.

Shagwell

I wouldn't go over .500 lift on untouched stock heads. You won't really see any power past there w/o a least some bowl work done. - stay around 480 lift. - also, you can pick up the GM LT1/Z28(.510 lift max) springs for around $30, springs, retainers and locks. thats really cheap insurance... - seing as though your car is a 90, I'm geussing speed density. - yet another reason to not go past .500. - My buddies' 89 GTA L98 car is running a 220/230@ .050, 497/502 cam. With a bowl job on his heads, a good trans the vette converter, and a ported stock intake and full exhaust he was running 13.7's @ around 99 mph.

AZZ28

Thanks for all the info so far, would be happy to hear what some
others think.

mnorton

Get this cam. It's a Crane cam part number CRN-104224 $269.88 at Summitracing.com

It is computer compatible with the stock chip and smog legal. Also you won't have to modify your heads for lift. Should be good for about 25 to 30 HP increase. New springs are still a very good idea with any new cam install.

http://www.cranecams.com/?show=brows...tType=camshaft

ZEEYAA

I would call comp and see what they suggest, also you dont want to get a cam that will outflow you heads/intake, but however you may want to take a look on the forums and see what mods you can do to the intake/plenum/runners that can be done for about free with a little elbow grease. And also look into some cheap headers, that will really help wake up the cam combo when you install, even with a set of cheap ones will outflow the stock stuff. And of course it would be a great time to replace the chain, especially if it has over 140k. GOOD LUCK.

AZZ28

So I am hearing from some of you guys around 20HP. I am assuming this is peak. I guess I would more importantly like to know "how much faster and fun to drive will it make my car on the street", meaing will it also imporve the midrange, and how significantly will it affect my low end torque. I am going to contact comp and crane but I figured I would ask anyone on here as well. By the way my converter is a stock piece right around 2000, and the gears are 3.23.

91Z28-350

The low end won't be impacted much, and probably won't be noticeable over the stock cam. You'll feel the mid-range more. It's not going to be like jumping in an LS1 and then going to your TPI, it'll be much more subtle but still noticeable through the butt dyno.

Go for the LPE 74216 cam. $115 from LPE, and it's better than the Crane cam, IMHO. The cams noted in the thread are designed for the stock heads and induction, with the exception of the ZZ4 cam. I don't think you can go wrong with any of the 3.

IMO, I'd rank in this order based on the specs, Comp most aggressive ramp of the 3, LPE, then Crane. Comp and Crane will be $250 or so. I'd get the LPE for $115 then when you get more mods (like heads and intake), or your new engine, get a different more aggressive cam to match your heads, and intake. I don't think it's worth another $130 for the other 2 on a stock setup, save the money for your next cam. http://www.lingenfelter.com/instructions_cam.htm for the specs.

You can do a search for the ZZ4 cam and timeslips, look for a setup similar to yours and the deltas. The cams will all be right around that range give or take a bit.

ZEEYAA

MAN 91-Z28 that is cheap, are you sure thats a roller cam, that sounds more like a flat tappet, I think he has a roller block, but if its that cheap I would go with the LPI cam for sure.....just currious about how inexpensive it is.

Shagwell

also note that his signature in his original post states that he has headers, etc...

- I too am suprised to see a roller cam that cheap...hummm what are the specs on that?

91Z28-350

Yes, the LPE is a roller cam designed for the L98 and LT1 engines. The specs are in the link I posted above, you need to scroll down for it as it goes through the 211, 216 and 219 cams.

http://www.lingenfelter.com/instructions_cam.htm . The link shows the ramp rate of the cam.

The gross specs are 213/219 duration @ .050 .493"/.502" with 1.6:1 rocker, .462"/.471" with 1.5:1.

That is an awesome price. The cam is designed for the stock heads, with the L98 in mind, from what LPE told me. The price has come down over time, but I've been watching it, as I think it's a really good value for a stock replacement cam. There's no need to try and stuff a ZZ4 cam in the the stock setup with this price. I've done the stuffing for ****s and giggles, but it's not worth all the additional measurement and "tricks" needed to get it to work with untouched stock heads. If I didn't need a new engine to begin with, I'd have used the LPE cam.

Shagwell

not bad at all. I'm not a big fan of 1.6 rockers in a performance built sbc though. Our rocker geometry sucks enough as it is. Thats why you gain so much from shaft rockers. - 1.5 vs 1.6 in stock replacement roller rockers doesn't really make enough more rotation torque to talk about, but when you're going for all you can get, shaft is the only way to go. Especially when new shaft rockers can be found for under $400.

- back to subject - for the money I'd say the LPE cam is a good choice, but to really see the gain you're looking for, you'd have to also get 1.6 ratio rockers...

91Z28-350

AZZ28,

The 1.6:1 rockers can exceed maximum lift clearance on a stock head, so stick with the stock rockers.

You can measure your clearance if you want to push it, but don't go to 1.6:1 with an aftermarket cam unless you know for sure how much room you have. It's better to be safe than sorry. Don't forget to add a safety factor to the measured clearance.

D's89IROCZ

If you are going to run 1.6 rockers ... you may need to open up the pushrod hole . The contact is closer to the rocker fulcrum. Then you are back at sqaure one . I did the ZZ4 swap . All I did was get SD1007( Scoggin Dickies) springs and screw in studs put in . That really isn't much work to make a cam work .
I have a ZZ4 cam with stock heads . Sure the lift is more than the heads want , but it's about increaseing the ramp rate not necassarily ( sp lol ) about peak lift flow numbers .


There is more to be had in doing the suspension up then from swapping from a little cam ....to a little cam. But I would do it right if I was getting into cams ...and put in screw in studs and all other associated hardware needed. Just hold out save your money .

mnorton

That's a great price on the LPE 74216, but I'm having a hard time understanding what the LSA number is....???

It looks to be an almost identical lift to the Crane 2032, with a little less duration. It seems to me that keeping the lift a little on the low side, and having the duration a little longer is a good idea on stock heads.

91Z28-350

LSA = Lobe Separation Angle. It is the angle between the intake and exhaust centerlines on the cam. If you've ever seen a cam, you'll see lobes pointing in different directions. The LSA is the angle between them.

You're not going to see much of a difference between the 3 aftermarket cams and the ZZ4 cam. You might as well go with one that fits (without head work) and is cheap. One is not going to give you 3 mph over another in trap speeds with the stock heads. Given that, go for price and the least amount of "to do" work.

The stock heads and induction are the limiting factor. Pulling the heads to just put on studs is a bit more than excessive. If you're going to pull the heads to put the same heads back on, you're better off porting and polishing and sticking a bigger cam in there than any of these....unless you really don't want to.

FWIW, the ZZ4 cam has slow ramp rates and is far from being aggressive like a Comp Cams XFI or XE grind would be. I think the Comp Cams cam has more aggressive rates than the ZZ4 cam. The ZZ4 cam really is lazy.

To be **** about the cams, you'd need more data. The LPE cam is spec'd. The ZZ4 cam is spec'd (I posted the data sheet a while back with all the durations at different lift points). The Crane isn't fully spec'd. Neither is the Comp Cams.

1bad91Z

iTrader: (1)

Comp cams Hyd. roller XR264HR-12 and the cam kit (springs, locks, retainers) would be your best bet.

ZEEYAA

1bad91-z , CAR: BET ENGINE: ITS TRANS:NOT!!!!! LOL..... NOW THATS FUNNY...... How fast is that thing?

1bad91Z

iTrader: (1)

Don't have a solid run in yet. When the car hooked, I fried a Mcleod clutch rated for 450 ft. lbs. I need to put a better clutch in it and some gears. When I get that done, I shooting for 11.9's in the 1/4.

Frying the clutch off the line and short shifting into 2nd, it ran a horrible:

2.54 - 60ft
9.02 - 1/8th
82 MPH

At the time, the TPS was reading 2 - 3 volts at idle (it was broken) and should have read .54 at idle. So in turn the plugs fouled and with the trashed clutch, hence the crap time above. I'll be doing the gears before too long and then a SPEC III F clutch. Waiting on new employment first though. When I get it all done, I'll post the timeslips.