Well folks, its about time to start putting together an engine for my 84 project. I feel like I've read a hundred threads on cams already, but I figure I'd ask for recommendations here too.

The Car: 84 non Z51, formerly auto but is getting a DNE 4+3 from an 85.

Uses: Nice weather driver for a 12 mile commute in the warm season here in Michigan. Some Auto-X events in the future. Running on 93 octane from the pump.

Goals: 400HP/400TQ at the flywheel sounds nice, but I think a broad, usable powerband is probably more important that peak numbers. I'd like it to feel faster than my 15 GTI that I sold prior to this car.

Rear End: Stock 3.07 Dana 36. Will probably get a Dana 44 and higher gearing in the future, but that's what I'm working with for now.

Engine: ZZ4 shortblock with <5K miles on it. As GM built it, no decking or machine work done.

Exhaust: 1.5" Headman long tube headers

Intake: Edelbrock Pro Flow XT with a Holley Terminator X EFI system. Needs at least 10" Hg of vac for the EFI.

Heads: Trick Flow DHC 175. 60cc chamber, 175cc intake , 74cc exhaust. Flow numbers are as follows:
Lift Intake Exhaust
0.1 65 53
0.2 133 104
0.3 192 136
0.4 233 180
0.5 258 198
0.6 254 207

With an 0.27 gasket, the engine is at ~10.0:1 compression

Rockers: I have a set of good Comp 1.5 rockers that came off the old heads I'd like to reuse. I'd only go to 1.6 if absolutely necessary.

Cams I have looked at..
Edelbrock Rollin Thunder 2204: This is the cam that came in the car when I bought it. Sounded great, performed terrible, as the heads were completely wrong for the rest of the engine at the time. (8.5:1 compression)
LT4 Hotcam: Seems like the consensus is its decent, but there's better options out there. Still, it seems to work alright in the ZZ430.
Comp XR276HR: Seems to be a good balance between power and an drivability. Larger grinds look like they trade overall torque for peak power.
Lunati 20080720: Was a recommendation from a friend. Not sure what to make of this one, many conflicting opinions in the net.
TIPS ZZ409: Looks like some folks don't care for it, but there are some members on here that have posted some nice dyno results with this cam in a 350 + AFR heads.

Be interested to see what you folks think..

 

Move away from the XR276 and go with the xe276. Same 224/230. I have the marine version in mine and it pulls hard everywhere for a 350.

 

Choose the cam with the slowest ramp rates, and the lowest lift you can stand.

This will allow the use of the weakest performance spring possible

Together these will ensure long valvetrain life and stability at high rpm

For example, I used TFS-30602001, a very low lift and slow ramp LS camshaft, which can support 800rwhp easily (currently at 600hp)

 

And just to clarify, the xe276 uses the milder ramps... its the cc503. The max you would make with those heads would be around 400/400... realistically with those heads and any cam in the 22x/2(2-3)x you'd be knocking on 400 crank. You'd be looking lower to mid 300s at the wheel.it would be a fun car.

 

Thanks for the recommendations guys, I'll take a look at the XE grinds.
When I bought the car in the summer, all I was going to do was fix the hood and headlight and drive it. I think I've got a serious case of whileitsappartitis!

 

Look up Buccaneer in the C3 section, he designed the Renegade CFI intake, has those cars down to a science.
Prefer cams with quicker than stock seat timing but not quick enough to hammer your valvetrain.
Being as you have a CFI you may not hit the rpm where float happens...I didnt have good luck with the XE stuff...need to overspring it a hair
Sleazy Rider has a nice Crower 221/230 which works well but not sure if your computer will play well with it.

 

He's using an Edelbrock proflow intake so he's covered. No CFI.

 

All the CFI stuff on this car is long gone. Carb swapped when I bought it, but it's getting a Holley Terminator X EFI system with probably an Edelbrock XT manifold. I've looked at other manifolds, but the XT seems to be simple and inexpensive. (Super ram is $$, stealth ram needs mods, mini ram is more than XT.)
I've also considered the Holley Stealth 4150 tbi setup on a traditional carb manifold, but again, issues with hood clearance.

 

Also @ChumpVette may have some input too. He seems to know a thing or several iirc.

 

Why get a cam with low lift and gradual ramps?. Get some good springs and snap the valve open at a higher lift if you want performance. Also, Chuck the 1.5” headers and get at least 1 5/8” unless your building for economy.

 

I was just going to post the same thing. I can't see any legit reason to not open the valves as fast as your valvetrain allows. You're just giving away power if you don't, and you don't gain anything in terms of streetability or economy by using slow ramp rates. I'd be looking at the XFI range, for example: like the 268, which should keep you pretty streetable and give a fair amount of power. Those heads seem to have a pretty low ceiling for flow at higher lift numbers without getting any special benefit at low lift, so you could benefit from some porting to wake them up.

 

When you snap the valves open quickly and increase lift, it will increase valvetrain wear and increase the potential for catastrophic failure (dropped valve type stuff).
It also makes the valve train more difficult to control at High RPM.

Finally, we make 1000hp with the slow ramp, low lift camshafts all the time. So it is completely unnecessary.
If the car or person in question is not using forced induction yet, often its a better idea to gradually teach them how to use forced induction with the low lift cam (1000hp of performance) rather than try to squeeze a 400hp engine for another 10-15hp by using potentially deadly, dangerous lift and ramp rates (not worth trashing an engine over 15hp unless you are actually racing for money or something)

 

So what would be considered a profile with a "slow" profile and what would be considered "fast"?

 

XFI is a fast ramp, XE is a slower just for example. The at .05 on the xdi is a 230/242 for example but the .006 is 280/288. The XE is a 230/236 and uses a 282/288 profile... The at .05 durations are about the same but the total duration is more on the XE meaning slower ramp. Plus the XE has lower lift for the same duration so less ramp is needed for the same lift. lower lift is slower, higher faster. That is the 2 factors I use to judge...

 

Well, you have to use the proper springs and a stiff enough valvetrain to manage the ramp rates, yeah. But if you do that, it's not a problem at all. My car had XFI lobes with quite aggressive ramps and it's still going strong at 12 years+ on the same valvetrain. This includes street driving, autocross, and lots of road course miles a sustained high revs. What you're saying is just silly. Lots and lots of heavily raced engines use aggressive ramp rates with no longevity issues at all.
So you make 4-digit power with eleventy-billion psi of boost, and you're worried about the "deadly, dangerous lift and ramp rates" that will "trash an engine"?!?!? And no, the person in question appears to have no plans whatsoever for using any kind of boost, so you're way out in left field with ridiculous recommendations that have nothing to do with his his needs. No engine builder would intentionally use lazy ramp rates, because that's just giving power away...and probably a lot more than "15hp." And that goes for naturally aspirated engines as well as boosted engines. What you're saying is just dumb.

 

Exactly, a well designed engine will have valvesprings which are able to manage a quick open and closing of valves with significant lift at a rpm high enough to make horsepower for the application. If you want tow truck hp, go for the slow ramps. If you want street/strip/track hp, get a performance camshaft and build around it.

 

If you understand volumetric efficiency you would notice that even the lazy ramp camshafts can generate a solid 95 to 100% VE at peak. The main advantage to faster ramps is a wider powerband, not necessarily peak power. It may not give any additional peak power at all, 15hp, 5hp, 0hp. The difference is negligible here.

Next, Lift can have an effect on port flow, but modern heads flow very well at low lift. In fact some flow better at low lift. Therefore the discussion of lift isn't as easy as 'more is better' because more is not always bette in terms of flow. The majority of modern daily-driven performance engines use heads which flow very well at low lift because factory camshafts use low lift anyways.

A stiff set of valve springs has a limited mileage. Many type of typical stiff springs require replacement after 20,000 miles to 40,000 miles. They are not suitable for daily drivers. You'd better be sure before you buy a spring if it suits your application is what I am saying.


All of this taken together applies to all engines, Nissan, Toyota, Chevrolet, etc.... It doesn't matter what kind of engine you are using. If the application is daily driver, reliability comes first, so the ramp must be slow and the lift must be low. Power is secondary to reliability. Since 1995 you can buy a 3L engine that makes 450rwhp using a factory turbocharger and camshaft with 200,000 miles of reliability. So when I see people struggling to make 450-500rwhp 20 years later and using valve springs with 20,000 miles replacement intervals and camshafts with so much lift they eat the valve guides it confuses me. twenty year old technology was able to surpass 500-800rwhp with 200,000 miles of reliability so what the hell are you doing with your super fast rate camshaft and ultra high lift trying to make 500 or less to the tire? Wasting time. Stop looking at the camshaft to solve your problems. It is making more problems for you instead.

 

I understand VE very well. It's also possible for a n/a engine to exceed 100% VE. But the point is, the cam with faster ramps will give you more VE if all else remains equal (advertised duration, total lift, etc). The main advantage to faster ramps is more power for a given amount of duration. You can either use that to keep your engine's running characteristics as they are and gain more power; or you can keep the same power and improve the idle vacuum, fuel economy, and low-RPM drivability. Your choice. But either way, the difference is not negligible. If it were, then every race engine wouldn't be designed with the most severe ramps the designer can get away with (where such things aren't regulated by the rules). This is even true for engines that have to last through 24-hour races. What you won't see is unlimited boost with shitty/lazy cam designs, because that **** won't survive. And again, you won't see on the OP's engine either, because he isn't building for a boosted application.

It depends on what you mean by "low lift." Every head has a ceiling where more lift doesn't add more flow. But in SBC terms, "low lift" means 0.1-0.3" lift. If your heads are making more flow there than at .5-.6", then you have problems! The OP's flow numbers are in his first post for all of us to see. He has small ports that seem to have a ceiling of about 0.500" lift. But even so, every millisecond that his valve is at or under 0.2" lift, it's only flowing half of what it does at 0.5". So I don't know what kind of crack you're smoking, but his power will be improved by keeping the valves up above 0.4" for as much of its open duration as possible. This isn't even open for discussion. It's just a basic fact.

You act like we're recommending some super-exotic parts that are only used on Top Fuel dragsters and have to get changed out after every run. That's ridiculous! A 268 XFI cam is hardly exotic, and it's not hard to get springs that will keep things well controlled for 100k miles. Again, my own personal car with XFI lobes went for tens of thousands of very hard miles without any problems at all, and it's still going strong. You're just making **** up to support a dumb argument.

I'm mostly just quoting in case you decide someday that it was the dumbest thing you ever wrote and you want to delete it. You're completely full of **** if you think mid-90s engines could make 800hp for 200k miles. That's when I know you're either trolling us or aren't worth listening to. Also, you see everything through the lens of aftermarket turbo setups. The OP doesn't have any plans for that, and there are a lot of good reasons not to want to mess with them.

To the OP: for the love of God, don't listen to this guy. He's either a troll, radically ignorant, or certifiably insane. Whichever the case, you don't want his advice.

 

Exceed... are you kidding me? 105% is so close to 95% that it is 95%. There is no significant difference between 95% and 105% since neither number can ever be much higher or lower. For example 110% VE is approaching impossible. 120% is impossible. You will never hit 120% with any cam head combo in terms of VE because there is a limit right around 103 to 107% where even with the kinetic energy of incoming air it forms a very high squeeze barely 5% above perfect with perfect valve timing at the right RPM. The number 5 is relevant here because now we can compare it to forced induction, which is 50 to 200%. So you telling me that a perfect cam/head combo at the perfect RPM with it's absolutely stunning 105% was worth all that trouble when forced induction MINIMUM will jack VE into the 150% to 300% range and higher range just by adding the blower or turbo? And leaving the OEM-like shitty 95% VE spring in the head and not worrying about what perfect RPM to shift because torque is 50% higher everywhere

The faster ramp will benefit performance, obviously. But VE can't go much higher than 100% in naturally aspirated. You MIGHT reach 104% or 105%. So when we look at the factory VE of 92% or 95% its the same thing as 104%. In other words, it wasn't worth the extra valve wear and potentially stiffer springs for more lift and faster ramps and having more valve components stressed out. Just for 10% or around that in VE? When forced induction starts at 50% extra VE and goes to 250%
Why challenge the engine's moving parts, all those already stressed out things and add stress to it that is completely unnecessary for the sake of 10% extra VE.... Who would do that? You can make up for the 10% with the boost controller by turning the dial one extra click to the right. Thats all this higher lift, faster ramp BS is worth, one click to the right on a boost controller. If you can see that then you won't waste your time doing it anymore. All I am saying is choose a spring that will go 150,000 miles if you actually want to drive 150k, does mileage matter to you? Not everybody cares about mileage they just want X laps.

Who are you telling that to? Why would anybody think that faster ramps would reduce power? Nobody is complaining about the power of a faster ramp.
I am only saying that in a daily driver or high mileage intention it isn't wise to increase the lobe ramp speed or lift beyond necessity, to give up the 10% of VE unless you are maxed out in boost 50PSI or something and need to reduce the boost pressure by doing head mods. Then your 10% would multiply by how many atmospheres of pressure was in the intake manifold so it could be come 30% or 40% at high boost pressure extra VE when we consider total flow at say 35psi of boost. But that isn't really a daily driver application... is it? Because if it is, then the additional stress of fast ramps and high lift may interfere with the longevity so the risk must be accounted for, I would tell you to just live with the 50psi of boost and keep the low lift, slow ramp cam for longevity. Because this is the rule of thumb when building a high output forced induction daily driver, you put reliability and valve control over power in the daily driver by the book.

I won't see unlimited boost haha. Just 18 to 28psi is fine for OEM 02-07 truck engines 800rwhp no issues, 150,000 miles using PAC 1218 valve spring. It's like 300lbs open iirc. That is plenty for 250% VE increase or whatever multiplier at 90*F intake air temp from a 4.8-6.0L style Gen3/4 needs. Highest RPM is 7,200 to 7,400 approaching 1200bhp at 4.8L Alcohol. Thats 1000 to the tire through a 4l80e easy with energy to spare if you really have that kind of pump and capacity in a daily driver. Managing the tank systems and pump heat is critical for 1200bhp daily driver alcohol application and I think alot of that is overlooked if you've never tried to feed a legit 1k the drink.

I will love to tell you what low lift is, in the context of daily drivers,
Low lift is the highest lift you can find for the engine that will work with the weakest valve spring that is still stiff enough to survive 15 to 30psi of boost and perhaps twice that in exhaust gas pressure at 3x to 4x the engine output. It doesn't take much spring to satisfy this. The main issue with OEM stiffness springs is that the valve blow open when the EGP begins to rise. This is common for almost all performance OEM engines because the factory puts an even lower lift and weaker valve spring for longevity in the first place, even in turbo applications springs often need upgrade to increase boost. So we increase the spring pressure but ONLY slightly, as little as possible, is fine and necessary. For example the cam in my 5.3 Gen3 is .560" Lift, slow ramp circle track grind. Its for engines that spend a long time at high RPM going up and down around in circles I guess? Is that what circle track is... But the emphasis is on valve CONTROL and valvetrain STABILITY which means you have to SLOW everything down, give it a very gentle ramp to settle back down and a gentle slope to open further impeded by the leaking hydraulic lifters, its a wonder the valve opens at all. But I'll get back to that in a minute.

Again, I know ramps improve early and late flow. I know it is more 'performancy' but again I will get back to that...

If you understand the risk fully because you have examined the lobe profiles closely of OEM and aftermarket cam manufacturers then you can free to choose any profile.

In the mean time, If you want daily driver status, you need the slowest ramp. The most reliable and stable performance, not the most power. Thats my opinion? Oh my god its just an opinion get over it

Please check statistics using Supraforums.com, Many 600-800rwhp OEM longblocks reaching 250,000 miles since 1998 with 600-800rwhp with USA version of the 2jz-gte.
I've inspected around 1000 Japanese engines from 05-2012 and installed many of them, 2jz-gte into cars here. Lighter cars...
And the minimum power I expect from the OEM 2jz engine is 600rwhp using a very gentle spring and low lift camshaft.
98-02' is a great range for 2jz-gte... if you can find it... it will do 200,000 miles and more at 600-800 at 3L OEM piston/rod/crank untouched bottom





Insane

I am extremist to show the full picture, sorry if you riled up. But here is the extreme version under glass.
If you are into performance and want to use a faster ramp camshaft to gain some tenths of performance from the valve opening event,
when what you really want is a solid roller camshaft.
Hydraulic rollers have no place or rate being fast ramp. Its a silly thing to do with a hydraulic camshaft. Increasing the rate of lift is going to increase the rate of piston oil leakdown inside the lifter, so the gains of the ramp are offset by the oil-piston interactions of leaking lifters and imprecise valve opening no matter what the lobe ramp looks like.
The solid roller fixes everything. You can use a very mild ramp and still extract incredible valve opening precision across the board for all valves even at idle. It will completely alter how the engine feels and sounds. And it doesn't need to be very aggressive to achieve this result.

To put it another way, it's chasing your tail with a hydraulic camshaft if your goal is to increase valve opening precision and rate, the only thing that can do that is a solid roller. And this has nothing to do with making power. Gaining 10 or even 20% VE is nothing in the search of power. True power is 200% increase in VE from almost any engine can seem like alot of power. So this whole solid roller all it really does it make the car sound cool at idle. You don't need super fast precise valve opening events to make big power, the big power comes from the compressor. I can make up for all the head mods and solid roller gains and super fast ramps and extra lift, with a single click on the boost controller. By that logic, all the extra ramp and spring and maintenance was for nothing.

 

I'm going to quote some of your extra special lines here, just because they are so entertaining and delusional.
There is no significant difference between 95% and 105%. Remember that, everybody, 'cause that is some factual **** right there. If you have 95hp and think you want 105hp, fuggedabowdit because it's no different. If you weigh 210lbs and want to lose weight to get down to 190lbs, fuggedabowdit: no difference. If a new car stickers at $40k but you want the dealership to come down to $36,199...yep, fuggedabowdit: just pay sticker price because it's insignificant.

Yinzcity, this is the crux of this guy's argument: all n/a engines are **** and you should ditch all your plans and put a blower on your car. Just in case you weren't able follow his insanity.

Right. It's a well-known fact that boost doesn't stress anything out in an engine. Supercharged and turbocharged gasoline engines always run forever and never have any mechanical problems.
That's not all you're saying. Obviously you have to choose the right valve springs for your cam, regardless of what it is. As I've already written, it's no big secret what springs to use with common cams that have more aggressive ramps. If you want a CC XFI268 cam, then CC will gladly tell you what springs to use. All of this applies whether your engine has boost or not, btw.

Yinzcity, I've been steering you so wrong! Kingtalon is right: what you should be doing is building 4.8L engine LS with 28lbs of boost that redlines at 7400rpm and runs on alcohol. It will last for 150k miles of hard use like that. It will cost less than your current plan and be easy to street drive. In fact, you should plan to commute in it every day, because this is by far the cheapest and most practical plan. How could I have been so stupid!




Hear ye, hear ye! Kingtalon has set the criteria by which he will grant us permission to choose the cams we want!

Oh ****, I misunderstood! Yinzcity, apparently what you really are supposed to do is find a Japanese 2jz-gte engine for your Corvette. Sorry 'bout that! All of this incredible knowledge is really hard to follow...

Dammit! Now I'm really confused. Yinzcity, apparently you can use your current build, but you have to select a solid roller cam and lifters for it. All that talk about valve springs that we discussed earlier? Forget it - that was just obfuscation. It's really all about the rollers. I will call Comp Cams and tell them they are silly because they offer cams with faster ramp rates for hy roller applications, and they will surely only last 15k miles. We should sue those *******!

What in the name of Good Googly Moogly are you talking about?!

I'm so confused. I thought turbos fix everything. Will a solid roller also fix the economy, cure COVID, and end world hunger?

Quote:

Insane

Well, we agree on one thing...

The important thing is that Kingtalon recapped his very cogent arguments in giant text attached as images. That's how you know this guy is legit as ****.