Marks69BB

I have a chance to get an almost new L88 cam and lifters for FREE. The question I have is how was your cam through the RPM range. Did you have plenty of torque thoughout the powerband. I thought I'd read a thread where you were planning on putting a new cam in yours; can you explain what was wrong with the old one or why you are wanting a new one? My motor now has a crate motor cam that is very mild and I'm wanting more hp and torque. I plan to use an electric vacuum pump for my brakes and accessories and will eventually swap in a Richmond 5 spd for the old M20 to go with my 3.08s. All other's comments are welcome too! :cheers: :steering:


[Modified by Marks69BB, 8:30 PM 1/11/2003]

Flareside

Remember that your crate engine won't have the same 12:1 compression that an L-88 has, so it won't be nearly as tolerant of a big cam. I think the advertised duration of the L-88 is over 300 degrees, and that's big. Are you ok with a lose of low end and a much higher idle speed?


[Modified by Flareside, 11:44 AM 1/12/2003]

Chuck Harmon

Mark,

Flareside beat me to much of what I had to say, and he is absolutely correct. To answer your question about its personality it kinda depends how and where you are going to drive the car. If I still lived in rural Colorado, I would not be tempted to change from the L88 cam. Driving in the city with countless stop lights, my eyes water at every one from the rich eshaust while idling at a mere 1250 rpm due to the aforementioned cam overlap. It is not happy to trundle through a neighborhood street at anything less than 2500 rpm. It hates any backpressure so you will need something like JCL's baffles which do a decent job quieting the car but can still be somewhat irksome to neighbors if you make to many trips to the store to get milk with it. And it is great fun to get milk with!

If you click on my url in my sig and go to the 69's page, you will see my dyno sheet posted at the bottom. It still puts out incredible torque at the bottom end (2500rpm+) that no street tires have ANY chance of holding on to. Some engines do make more torque, but I will out pull most of them quite handily in the upper ranges. More torque won't help if you can't hold what you already got! And I don't think they can hold it any better.

I have already bought and received a Crane roller cam to be installed along with some other choice goodies once I get some free time. Hopefully Pacin will be on hand to give me a hand and moral support. Oh, the hours of Bench Racing I am looking forward to. Anyway, the cam should make the car much more tractable at lower speeds, more like a factory LT1 cam I expect, yet still keep the utterly ferocious personality at the upper end.

It is the ferocious part that I most love! The engine has a very nervous feeling to it once it starts to come to life at a little over 2000rpm. It constantly begs you to let her loose. When I do, I swear the Banshee scream is yelling YESSSSSSSSSSSSSS! Even though my horse power peaked at just below 6000, it remains pretty flat after that. I typically shift at 7K when I am playing hard. If you were to shift when you feel the engine truly begin to let off, you would be shifting closer to 7.5-8K.

I am probably too self conscious about bothering others. if I wasn't the sensitive guy that I am:blueangel: (:U ), I would keep the cam. It is rude, obnoxious, and loud, but it sure is ready to please when the opportunity arises. But it is more work to drive the car with it.

But unless you have some serious compression, you will be going backwards if you try to use it. It actually makes less cylinder pressure below 5000rpm than the 435 tri-power cam which is why I can get away with less than 100 octane fuel for the street. It is only above 5K that the pressures equal the high levels of the 435hp cam, but they do it at a much higher rpm. It is the overlap that allows so much to bleed away at low rpm’s, but it is also the overlap that takes into account the momentum of air/fuel mixtures that keep this bleeding away of pressure away at high revs permitting the cylinders to continue receiving an adequate supply of said mixture. Lesser cams just don't permit enough valve timing and lift to fill a big cylinder in 0.00429 seconds @ 7,000rpm.

The roller cam will give me a somewhat smoother idle, lower idle speed, more than my current 7.5" hg of idle vacuum, less raw gas spewing out the pipes to burn my eyes and those within 20 feet of the car, better mileage (which is what driving Corvettes is all about), more torque, and maybe enough extra hp to break the mythical 500rwhp threshold! I actually think I could probably break it now if I were to spend a day on the dyno tuning it. Adding only 17 more hp with jet, timing, valve adjustments, spark plug changes, etc. when I had only tuned it by SOTP shouldn't be too much of a surprise.

As I said earlier, I don't really even need the extra torque, but it will be nice while highway cruising in 6th. I will have more available torque in 6th at 2200rpm (approx 75mph) to out accelerate most any other car even if they use "passing" gear.

Mark, this really gets into more stuff than can really be covered on a post. If you like, e mail me your phone number and I would be happy to give you a call and go into this more. This is fun stuff!!

Yet I would need to call you soon in that we will be leaving for vacation on Monday. I'll be gone for 9 days.

Chuck

69ttop502

Chuck, do your power brakes work with without running a can or anything? I am also curious as to what octane you need to run. I am asking because as Joe has seen on the Chevelle site there is a guy there that has come up with a program to measure dynamic compression and according to the program with my cam I can run up to 11.75 static not counting variables like elavation and such. Any thoughts? Also Chuck, fill us in on some of the aforementioned other goodies making their way onto that L88. Bill.

P.S. Mark sounds like you are coming along with the motor. Keep it up.

Chuck Harmon

69ttop502,

While not as strong an assist as when I was running the L46, It is still adequate. The PB's were too sensitive to heel toe with the L46, much easier to do smoothly now.

As for my goodies list:
1) McCleod dual disc clutch with small aluminum flywheel
2) New power steering retrofit, doesn't need horizontal ram tube. 12:1 steering ratio.
3) Bisltien Sport shocks
4) Fluidamper balancer
5) Crane roller cam

Chuck

DJ Dep

Chuck: You are getting OLD :(
Here I am looking for the factory ZL-1 cam (.560/.600 lift and 347/359 duration) or the ZL-1 fuel injection cam (.600/.600 lift and 360/366 duration), and you are installed a sissy-butt cam. BAH! You are disillusioning me! :mad

Dep :D

Chuck Harmon

:troll :troll :troll

Sissy Butt!! How dare you old geezer! :boxing

Such words are uncalled for on such a civilized forum!

Chuck :mad

Chuck Harmon

Dep,

OK, I got that out of my system. Yeh you're right, I am a sissy butt afterall! The duration on the new cam will only be in the low 300's, not mid 300's.

Chuck :D

DJ Dep

Next you'll be replacing that L-48 Caprice motor and installing fancy new cupholders. What is the Rat Pack coming to??? :cry :cry :cry

Dep


[Modified by Dep, 2:51 PM 1/12/2003]

67HEAVEN

Geesh, I've got a 180 cam laying around the garage that is way too civilized to use in the new engine. ;)

DJ Dep

Well you can always use old cams for fireplace pokers or to turn bar-b-q coals with ;)

Dep

67HEAVEN

Not sure what I'll do with this 3959180 cam, but I probably won't be stirring any fireplace ashes with it. :lolg:

Marks69BB

Thanks to all you guys for the replies! :cheers:

Chuck - What specifically are you havin to change out for the new Crane roller and which cam is it?

69ttop502 - I'm really strugglin with whether to replace these low compression r-port iron heads/pistons since they seem to be in the way of my plans for a new cam.:confused:

67Heaven - Just outa curiousity, is that the original L88 cam? If not, what's the brand & specs on your unuseable cam and why was it surplus?




[Modified by Marks69BB, 8:30 PM 1/12/2003]

67HEAVEN

It's #3959180, the ZL-1/LS-7 cam that I ran for years.
Solid .560I/.600E lift, .262I/.273E duration @0.050 lift, 135 deg overLap, 427 ZL-1, 454 LS-7

I'm dropping a new engine in the car when the body and paint are completed, and I'll likely go all new.

DJ Dep

Big block stock mechanical cam specs:
Original L-88: #3925535 .540/.560 lift 326/334 duration

ZL-1 #3959180 .560/.600 lift 322/334 duration

Can Am Off road: #3994094 .600/.600 lift 366/334 duration

Dep :chevy

Chuck Harmon

Well guys, I'm just about outa here for the next 10 days. Goin somewhere warm tomorrow. I think it's called C3 Forum Deprogramming!. Please note that this post, #2001, takes me to a new level. I ask that you lesser posters, and baby you know who your are, face East when you next speak my name! In truth, I will be West of all of you except Maurice. Yet if you do face East, you will probably be showing me your best side :D

Aloha,

Chuck

Marks69BB

You're:leaving:?

Sounds like you won't need a coat where you're going and sunglasses and swimming trunks is all you'll need to pack. :cool: :cool:

Enjoy the break and drink some :cheers: for us while you're there! My questions can wait cause I'm in no hurry to change the cam just yet. Will talk to ya when you return to the madness. :seeya


[Modified by Marks69BB, 10:14 PM 1/12/2003]

Solidlifters

A couple more camshaft comments: There were 2 L88 camshafts, so I guess the question is, which one are you contemplating? The first design was in all the L88's that were closed chamber (12.5:1) and the second design in the late open chamber L88's that were 12:1. The second design is the same as the ZL1/LS7. Crane and the General Motors Performance Parts Catalogues confuse this issue by incorrectly referring to the L88 as 435HP, instead of the correct 430. One other comment, the 435 tri power cam is of course the same as all the 427/425 cams and the 396/375's, with the exception of the Z16 375 which was hydraulic.

I only have one car with the second design L88 camshaft, a 69 Camaro with a LS7 crate motor. My 69 L88 Corvette, being early, has the first design camshaft. I also stuck this cam in a 427/425 Biscayne clone which is only 11:1 based on my experience with a 67 427/435 coupe, which a previous owner had installed an L88 cam, intake and carb along with the rest of the original engine components and felt noticeably stronger through the gears than the 435 did stock, even with the 11:1 compression. I personally like the first design camshaft for a street car, and my L88 which is pure stock, right down to the smog pump has power brakes that work as well as any other car.

Marks69BB

Not sure which it is. This cam is an aftermarket repro and is coming out of a Gen IV 454 L89 racing clone (427-435 with aluminum R-port heads and tri-power setup) that had 13.5 to 1 CR. Is there any simple way to tell the difference between the two?

Solidlifters

The only ways I know would be either get a part number that's usually stamped on the front or rear on an aftermarket cam and call the manufacturer, or go through the checking process with a degree wheel and dial indicator with it in an engine with 2 lifters and pushrods.