I've posted this to a couple places yesterday and I still have got a good answer yet:

I will be the first to admit that I am completely cam illiterate. I'm gonna do some research on this stuff tonight cause I know I have some literature at home. But in the mean time, can anyone explain the difference between these two cams and tell me if there is a benefit of the LT4 over the L98 cam and for what reasons if any.

L98 Cam:
The duration at lash point in degrees (intake/exhaust) is 294/294; duration at .050" tappet lift (intake/exhaust) is 202/206; and maximum lift with 1.5:1 rocker ratio (intake/exhaust) is 403/415. Valve lash is zero/zero and lobe centerline is 115 degrees.

LT4 Cam:
The duration at lash point in degrees (intake/exhaust) is 279/287; duration at .050" tappet lift (intake/exhaust) is 218/228; and maximum lift with 1.6 rocker ratio (intake/exhaust) is 525/525. Valve lash is zero/zero and lobe centerline is 112 degrees.


Also, any comments on CompCam 1.6 roller rockers as opposed to the GMPP rockers ( https://www.spoperformanceparts.com/...=773&CATID=764 )? To me the GM parts are looking better, but if someone can comment otherwise?!?

 

Lift is a concern here as the L98 only makes 0.403/0.415 lift with 1.5 rockers.

Back off the LT4 numbers to 1.5 ratio and you get 0.492/0.492 lift...

This sounds like the LT4 Hot Cam numbers to me.

LT4 gives significantly more lift over your L98.
The separation b/w intake and exhaust is less on the LT4 than L98 producing a good amount of overlap and is geared towards higher RPM running and a rough idle.

Anyone know what max lift is for L98 springs? I'm not too sure but I think with 1.6 rockers and >0.500 lift your going to need new valve springs. Heck with L98 heads (they use half moon design?) You may have to worry about piston to valve clearance too with that kind of lift.

The 1.6 rockers are good, the roller rockers there just may fit ok.

How's price though to you? Those must cost a good amount...

 

People on the TECH board will say anytime you upgrade from stock cam to replace the springs, cuz they're junk.

I wouldn't go past a .470 lift as I believe that is there rating.

 

i dont know if your motor could really support that LT4 cam with 1.6 RRs right now, you dont have any real mods, excpet i guess a TC with a slightly higher stall than stock. maybe it could, hydraulic roller cams are different than hydraulic flat tappet ones, in that you can run alot higher lift and still maintain driveability. either way to see the full gains of a big cam you are gonna need some headers and sometype of modified intake setup and some head work.

 

I knew I should ahve just asked you guys in the first place. First off, thanks to the three of you for your responses. Now to reply...

Slade1: HOT cam is right...good one. I wouldn't even think of putting my stock springs back in with a new cam and greater lift. I was looking at the LT4 springs but I'm under the impression that they might not be up to the job. Apparently they were designed to work with the LT4's light valves and there's a question as to whether they have a high enough spring rate for my stock valves which are heavier. I don't have a clue here so any opinions are welcome. Do you really think valve clearance might be an issue??? As for price, I'm working on a new TFbM dealer discount as of today actually. I'm hoping it will be finalized as of next week and then I'll get prices as of that point. With 35% off list price they shouldn't be too expensive I hope.

Mark: Thanks for the input.

darbleinad: Totally understood. I am fully aware that I need headers and I'm hoping to pickup enough money over the winter months to be able to afford a set. As for intake, I can't afford a Superram, or the likes, so I'm stuck with my TPI crap. That will have to be further down the road. But depending on costs, if I decide to go forward with this, I'm thinking of having my heads machined and ported.

Just so you're all on the same page as me, here is where my thinking is...I can't afford to have the whole motor down over right now. Ideally I want a 383, but I don't have all the other components like headers, heads, intake, etc. that would go alone with such a motor. So I figure, rather than sit around for the next two to three years and try to save up for everything all at once, maybe I'll do a little bit at a time?!? Am I steering myself wrong here? I would like to hear you opinions on this please.

 

nothing wrong with doing a little at a time, but with when choosing a cam, remember that more displacement makes a cam act milder, ie a cam that is very aggressive in a 350 will not be as agreessive in a 383. so if you buy a cam now for the 383, you will likely give up some drivablity and low end in your 350. on the other hand if you by a great cam for a 350, you may be leaving a bit on the table if you put it in a 383. everything else, roller rockers, headers, ported or aftermarket heads, aftermarket intake will make your 350 better for now and help even more when you put them on a 383.

 

How about buying a great cam that works on border line for drivability with 1.5 rockers? That's always a possible option.

1.6 arms can always be an option if the 383 with that cam combo is mild with 1.5 arms.

As for the L98 heads, I'm really not sure about piston to valve clearance. Unless someone here knows the limitations there I have not done the actual measurements.

First you have to determine clearance, you need to know what clearance you have at TDC from the piston, then gasket size comes into play, then chamber size on heads. A trick I've seen used is bringing a chamber to TDC placing some clay on the piston then placing the head on. You get a nice 3 D mold of how much clearance you have. The half moon design is what I'm not sure about... you have angled plugs?

Your options are only limited really by your wallet.

I say do a little at a time, enjoy the engine, then mod again.

Besides, there's always guys like me that wouldn't mind taking that L98 cam off you...

 

slade...why on earth would you put that L98 cam in your engine? sure its better than your factory one, but it still sucks. if you are going to the effort of swapping cams, at least put a good, aftermerket one with some decent lift numbers in there.

 

One reason:

Used L98 cam = $50 CDN
Used LT4 Hot cam = $275 CDN

RP.

 

Agreed.

 

Paric, couldn't have summed it up better than that...

 

Imyself am a ZZ4 cam lover.. all I have heard is good things about it.. seems to be a good medium for all mods.. The hotcam is some what radical.. but I like that in people!! hahaha
Just make sure you get the right heads when you get you cam..

 

Hey IROCKER I've been looking at alot of cams lately as well and see the ZZ4 as the best candidate for the buck (of course that depends on where you shop).

The specs are 208/221 and .474/.510 with 112 LSA. Need new springs but that is no surprise. The duration is pretty strong on the exhaust side mild on the intake. Very streetable.

I am sure you can find much bigger numbers from other cams but they cost alot more too. I can buy an AFPR and timing chain for what I save on a ZZ4.

No matter what you choose you have to get head work if you want the cam to make power.

thx,
RP.

 

Any one of these cams isn't going to generate any clearance problems. You need 230+ duration, lots of overlap(LSA) and lots of lift to smack the pistons. All the cams listed so far would work great. My choices are.......

LPE "211" cam (if you plan on doing head work in the future)
LPE "216" cam (if you don't plan on head work)
Comp Cams EE 218/224
Comp Cams CCC 210/220

I wouldn't install an aftermarket cam without a spring change. I doubt Chris would either.

 

Wow, lots of info! I'm on my way home from work now so hopefully I can plug through all this stuff when I get home. Thanks guys.

 

Palric,

you can find good aftermarket cam for a 305 for less than 275.

 

Hey Brad really ? In Canada ? I've been calling around and it seems that COMP or Crane roller cams (which IMO have the best grinds) always ends up $400+ with tax, chain and gaskets $500. Decent push-rods and springs are another $150.

I can get a new ZZ4 roller for just under $200 CDN. Add push-rods, roller chain, springs and gaskets and it totals around $450. Now I know the COMP and Crane cams are hotter grinds but I have to cut corners somewhere. Also, with the 474/510 lift I won't need 1.6 rockers -- save a few more bucks.

well thats my story,
RP.

 

there you under 200 for a good the cam. you say all the opther stuff adds and it sure does. so then why, when changing cams and all the other assorted stuff would you put a stock L98 cam. you have to change all the other stuff. why go to all that effort and cost to throw a piece of **** came in. that was my point.

 

Okay...finally time to digest all this stuff:

Brad: I guess worst case is I have to get another cam for the 383. As long as the other stuff is reusable on the new motor than it's not too much of a waste is it?

Rovic: If I do get another cam, then I'll consider my L98 cam sold.

Gerrit: Is the ZZ4 cam you speak of the same as the LT4 cam? I know they reccomend a lot of the LT4 stuff for the ZZ engines...just checking to see if we are talking about the same thing or if there's another cam I should be looking at.

Richard: Same question...is the ZZ4 cam the same as the LT4? And yes, I'm hoping to afford to get my heads done as well. I realize it would be very limiting otherwise.

Acceld: So you're saying the LT4 cam with the 1.6 rockers should be a safe bet as far as clearance then?

Richard (again): When you say $450 for the parts you listed, are we talking $CAD and brand new? That seems pretty cheap if that's the case....and I'm hoping to get things a bit cheaper with my dealer discount.

 

If all you do is change the cam, you'll have no clearance problms. It's when you start changing pistons and cutting the heads that clearance starts to get close. The ZZ4 and LT4 Hot cams are different. The ZZ4 has .208/.224 (i think) and the LT4 hotcam has .218/.228. The ZZ4 cam is pretty mild and it would probably work great with what you currently have. The hot cam is going to like siamese runners and an aftermarket base as well as some PROM work.

As for your question about rockers..............

GM saw fit to offer the warrentied LT4's with those rockers. They are made by Crane. GM made Crane modify the existing Gold design to allow for longer life. They are tough and well made but so are the Comp Pro Mags. I chose the Comp Pro Mags because they have stainless steel bodies and they are rebuidable. Either one will work great for a long time.

 

I talked to the guy that built my engine about a month ago, about putting in 1.6 roller rockers. He didn't recommend it. In his opinion, if I wanted to do it, I should put screw-in rocker studs in. I don't know if that's really necessary, but there is some logic to it.
According to him, just going rollers will make a difference.
If all this is true, wouldn't it make more sense, to go with a higher lift cam and 1.5's rollers?
Just a question, not looking for a debate.

 

Well, the thing with most roller rockers is, they're NON Self Alignging, which means you'll need screw in studs so you can use guide plates. Then you'd need hardened pushrods.

 

Crane makes some self aligning rocker arms, gold aluminum extruded ones I recall, but they're damn expensive and the gain is not justified by the cost compared to other 1.6 rocker arms.

 

It all boils down to this..........you have to pay to play.

Those that don't can continue to run 15's.

Currently, only Crane and Comp Cams make self aligning full roller rockers. Unfortunately, they both only sell the self aligners in their premium lines.

 

OH Really....

 

 

wow I missed out on all the fun.!!..lol Anyways..IMO screw in studs is a must ..roller or non-roller rocker arms..FYI guideplates version are more stable than SA versions..

Theres more to cams than the specs..Two cams might have the same "specs" but can behave totally different..IT all depends on how steep or where the bulges,dips and or peaks of the lobes are..As for the GM cams they are mass produced so the tolerance has a wider degree of variation(thats why you degree the cam)..Also the GM cams might say the same specs but actually milder than the aftermarket counterpart..With that said why waste your time and money on a cam thats not the best for your engine??To do it later meant a lot more expenses..gaskets,fluids,chemicals,hand cleaners and time.

IROCKER,

I wouldnt waste my time on an L98 cam..Its even more of a generic design than the ZZ3 cam(same cam is used in the ZZ4).Going to big is worse than going too small.

Cam is the brain of an engine..

Daz

 

Ok I see what you meant.

Yah -- I wouldn't go through the hassle of a cam change on an f-body unless the numbers (duration & lift) or the expected results really justified the effort.

RP.

 

Hey Chris this cam stuff will boggle your mind eh ? And it always leads to more questions...

The ZZ4, LT4 and LT4 HOT cams have GM part numbers but they are different. Sofar I have collected this info:

ZZ4 specs are 208/221 .474/.510 @ 1.5 with an LSA of 112.
LT4 specs are 203/210 .476/.479 @ 1.5 with an LSA of 115.
HOT specs are 218/228 .476/.479 @ 1.5 with an LSA of 115.
LPE 211 specs are 211/219 .503/.525 @ 1.5.

I've also read that the ZZ4 is NOT computer friendly some guys say they have done up to 10 burns before they got it (the chip) right. (I don't know about you but that stands my hair on it's end). I've also read the LT4 cam is a very friendly bolt in but then look at the LSA you could practically dispense with your EGR with those numbers. Thing is the LT4 and LT4 HOT goes for alot more $$$ than the ZZ4.

I am doing flip-flops on the cam upgrade. Yes do it -- No don't do it. For examples sake, here is why -- you can get a Ramjet crate motor (for bajillions US $$) that is spec'd at 1hp per cube. It's cam specs are 198/209 .476/.479. How come this thing makes 350hp with "peanut cam" duration ? To find out why I went to the GM Perf Parts web page and checked out the motor which had these bright shiny aluminum heads. Recently I talked to a guy who builds circle track motors you know the ones restricted in cam size and cube and intake size ? His story was basically this -- given a very mild cam but with the right heads and/or head work on a 4 inch bore block he can make 500hp any day of the week. So then I read some books on SBC cams and heads (David Vizard).

My conclusion is heads make the power and cams determine the range of power. This led to another question, why change cams at all ? That is -- if my range of power is sufficient ? It is after all, a TPI motor.

My factory cam is somewhere around 203/209 .415/.430 (depending on sources). Throw on some 1.6RRs to get a little more duration & lift and it starts to look like an LT1 cam. Can I make 1hp per cube (out of my lowly 305) with the right heads but with this factory cam ? I have a pretty decent exhaust system, could use some headers. Upgraded ignition but could use an AFPR. Maybe TPI coud use some more porting.

Hahaha more questions... the way I feel today I am too lazy to re & re the freaking cam. Been there and done that. Eventually I'll swap in a 350 and upgrade the cam before the engine goes in the car.

Oh yeah -- have any of you checked out ARAO heads ? 32 valves for $10k I can make my 305 think it is a Porsche hahahahaha...

too lazy to do a cam swap,
RP.

 

The Hot Cam has a 112 LSA. It's lower nemerically LSA numbers that increases overlap. The ZZ4 cam will be quite happy in a mass air car with no PROM work. It won't be optimised but it'll run fine. Here's the link to the GMPP site with the cam specs on it..........

https://www.spoperformanceparts.com/...html?CATID=826

 

Oh man, my head is spinning with all this info.

Paul: I thought those rockers looked familiar. I've heard of others that are happy with the ProMags as well.

Daz: Not sure what you mean...I have the L98 cam right now in my car. So do you have any suggestions? LT4? ZZ3/ZZ4? None of the above?

Richard: Paul mentioned that the ZZ4 is good for MAF cars. When you say it's not computer friendly, are you talking all TPI or SD? As for the rest of your post...sounds like you're in the same boat as me.

Paul (again): So you believe the ZZ4 would work good with my current setup (and the addition of some headers)? What about a 383 later? I'm guessing it might be to mild possibly? I'm fully prepared that there is the strong possiblity that what ever cam I get now I will have to get another for the 383 anyway...just curious though, cause anything that's reusable is a bonus.

 

I think the ZZ3 cam would be good for your motor..BUT something from Comp or Lingileler would(should)be better..

Opinion of the week:To those who wants to keep their stock PROM chip,be prepared to stay in the high 13's or go carb..IMO IMO IMO In My effin Opinion..lol Im drunk

Daz

 

I have a Lingileler cam

 

I would say if he wanted to go to the trouble of bringing it to the 383, may as well run a LPE cam.

I think he could get one with a good separation between intake and exhaust that won't f with the ecm that much and still make a good amount of lift that it will make the 350 run pretty decent.

The stock TPI intake will become the restriction, but doesn't daz have a superram lying around hehe?

 

Yah I have SD so I have to be careful of duration and LCA cause I don't want to get into PROM burning. I've never had a MAF car but I gather they are far better at adapting to mods than SD. I know SD can be very finicky. I've done more board searches and have found enough threads saying ZZ4 = NOT happy with SD cars without major prom work.

If I do get some sudden urge to re & re my cam (not likely I'll pull the freaking motor first) it will be to install one made specifically for a TPI -- something from LPE, SLP or TPIS (guess I agree with ACCELDZ after all). I've read enough negatives about grinds that 'should work' with TPIs that instead perform marginally or poorly then you spend your days trying to recover your driveability burning proms screwing with this and that groping in the dark for answers blah blah blah...

You know how it goes the only thing worse than spending big bucks on a roller and going through the hassle of installing it, is afterwards finding out you've made a poor cam selection and the car runs like garbage. That would be intolerable I know because I have been there and done that before.

But I am more interested in heads, headers and improving the TPI. I've already picked up 3.73s, just about to order some headers. I expect to have the heads off so why not upgrade the TPI while it is apart ?

Got alot more bolts to undo...
RP.

 

Is that where you sleep? that looks so comfy... hahahahaha

 

Rovic: Correction, Daz had a Superram lying around...someone beat me too it! I was very disappointed. Win some you lose some I guess.

 

Hahahaha only when the wife kicks me outta bed !!!

 

Well one things for sure......Daz's next engine won't be fuel injected Which can only mean one thing! Big block or 400 with a carb. I have a sick feeling Daz will be back next year and be back bigger and faster.

 

or maybe ill just sell the whole thing and get buick regal v6..xmas wont happen this yr ..

wanted:305 roller block..not bored..pm me pm me pm me pm me pm me

daz

 

S-u-r-e-l-y you jest ? Daz + 305 ?!?!? Must be for a neighbour.

Hey STIFFLER is looking to unload his 305 he has a 350 swap going.

RP.

 

sorry but no.. I am keeping the 305... I have bilt this 350 and my luck it will blow up after 10seconds... and the 305 will be going back in...

 

Heheh, I blew mine up in under 5 seconds