L-88 Bumpstick Help
Done a lot of research on the L88 solid cam 427.
you would think it has one set of specs. I have found
3 different sets of grind, duration, lift and lobe sep numbers
on this thing.
Because it has that fast chop idle the intake/exhaust vary in degree
and the lift varies in degree as well. What I have found most is the
264/269 dur, .560/.580 lift.
Does anyone really know the truth on this?? please. The oldie GM part
number was/is 3925535 ?
I was leaning towards the Isky 396245, Z-45 grind, but it wouldn't give me
the L-88 427, solid Yenko type beefy/throat sound/idle. you guys know that
old power sound.
Do you want to buy a L-88 cam or the specs.
Crane makes a "blueprint copy replacement" for the gm#3925535 67-69 L88cam
If thats the cam you want go buy it and stick it in your big block.
Make sure you have long slot rockers and some springs that will handle the lift.
The isky 396245 cam is more like a GM LS6 L-72 427-425hp cam than a L88cam.
The duration is much shorter and less lift.
If you want a Isky cam that will most sound like the L-88cam then ISky #396277
Z-77 is the cam you want. It will be very close in actual sound.
Needs a good bit of compression and gearing. Just like the old L88 it wants to rev.
There was a early 1967 version GM L-88 cam that is 256 269 112 .559 .580
GM does not make it nor does crane because it was soon supersedded by the GM #3925535 cam in production and service parts.
Crane cam #134691 F-290-2 is the closest match replacement and will "sound the same" at idle.
There is also a GM ZL-1 427-430hp LS-7 454-465hp cam 262-272 .580 .600 112 used on 1969 and 1970. and the LS-7 crate motors.
old GM PN 3959180 This became the "service replacement" for the L-88 cam with new upgraded valvesprings back in the day as it made more power.
Both need high compression and lots of rpm in the real world.
Whats with the big fixation with these old GM cams?
Comp cams "magnum muscle cam" comp # 11-551-5 CB280S-10
Makes a much nicer driving replacement real street for any of these cams (especially in a street pump gas motor). You'll be hard pressed to tell the difference in idle between this cam and a L-88cam in a 427 or 454, but you will like it overall, much better.
Especialy if you actually drive your BBC powered car as opposed to just listen to it idle.
A modern BBC street cam design that makes more power and more torque right where you need it for a strong modern street/strip muscle car motor yet "drives" very well.
Think of it as a "LS-6 cam on steroids". Very cool idle. Will not leave you wanting, there.
Last edited by F-BIRD'88; 10-15-2008 at 05:31 PM.
F-BIRD'88, L-88 Cam Advice
Of course I am going to drive it. I just like the sound of that
L-88 solid cam.
I am not sure if this will work, but cut/paste the link
above tolisten to the BBC sound I want.
Comp grinds a hydraulic re-pop of the LS6...
Hyd. 1800 to 6200 Part number 11-670-4, Grind number N+LS6, 276*/283*, 229*/236*, 0.530"/0.524", 112° LSA.
Back in the day, those nasty factory cams were ground with quite a lot of ramp, 65 to 70 degrees difference between 0.006" and 0.050" lift figures. Today's grinds are much quicker. You'll note that the difference on the Z45 is only 34 degrees. That's only 17 degrees on each side of the lobe, opening and closing, assuming a symetrical grind on the lobes. If using that cam, pay strict attention to using all of the supporting parts such as the recommended valve springs. Break the cam in with some worn-out stock springs, then change them out for the recommended Isky units. Use plenty of ZDDP in the oil.
I would think it is possible to contact your favorite cam grinder and have them grind an L88 cam to the same specs as the factory grind. I'd bet they still have the masters.
F-Bird posted while I was still typing and has given some excellent information.
and having built a few BBC's with these cams (we would build our own versions of them using the service parts.) I highly recomend that if you are building a 396 to 454 street BBC that runs on pump gas I recomend the Comp CB280s-10 cam for you. it will sound the same.
The cam I liked the best back in the day of the old BBC cams was the GM LS6 454-450hp 143 cam.
You didn;t get tired of it on a daily basis like the L-88 and ZL1 cam.
They were (and are) just too big for street driving. (especialy with an automatic)
The LS6 or comps magnum muscle replacement #11-551-5 is much nicer cam.
If you want a HYd equivelent use Comp #11-250-3. Another nice BBC street cam like the old LS-6 cam.
Don;t worry, the idle will be plenty nasty.
Last edited by F-BIRD'88; 10-15-2008 at 06:11 PM.
F-BIRD'88&Techinspector, LS6, L88 stick Questions
that comp# 12-250-3 is for a SBC not BBC
Which comp cam would be better for all out grunt
out of the hole in your seat and sound the nastiest?
the 11-670-4 or the 11-551-5 Comp???
Liston to this again please..everyone..this is a nice sounding
ride and performs well. A friend has one (clone) and it is in your
11-551-5 is a much better cam. If you want a "muscle car cam" this is it.
11-250-3 is the closest hyd version.
All these cams have more lift than the old GM cams and will make more power with modern heads and or porting than the old stuff.
I don't have to listen cars on U tube. I owned cars with the cams you're looking at.
The L88 cam came in a 12.5:1 cr motor that ran on "Sunoco 260".
Essentually todays race gas. When you drop the compression ratio to a streetable cr that will actually run on 92 octane gas without detonation, the L-88 cam gets real lazy in the bottom end (where you do the majority of your driving).
Not your best real world choice.
A real deal origional 427-L-88 Nickey Nova would run mid 12's in OEM trim and 12 flat at 116 with open headers, traction bars, slicks and 5.13's back in the day.
My 9.8:1 400 vortec SBC runs faster than any of the old stuff from back in the day. and drives a lot nicer. Modern tech. Plenty nasty idle.
Last edited by F-BIRD'88; 10-15-2008 at 06:36 PM.
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