L78 motor cam opinion's
 

Ok guy's looking for some input. I am going to build my 68 L78 motor this winter. I bought a complete stock short block assembly. I was told buy the guy I bought the motor from that it has this cam in it!

Crane energy part number is 11-678-5
lift 590 intake 598 exhaust
advance duration 282 intake 290 exhaust
110 lobe seperation
16 thousands valve setting
2400-6800 power band

Do you think it is to much or is this more of a race cam than a street cam. He ran 50 thousands head gaskets to lower the compression. He said he had no problem with motor running on high octane pump gas.
I could order the stock cam but I was told buy a couple of people they went with a bigger cam and it helped the performance. Just looking for some input from others.

Thanks

Re: L78 motor cam opinion's
 

My black Gibb nova had a cam with 627 lift in it, worked fine on the streets. https://www.yenko.net/ubbthreads/imag...iggthumpup.gif

Re: L78 motor cam opinion's
 

The engine builder who performed the machine work on my big block did not particularly care for Crane Cams. He suggested I use a Competiton Cam. He stated that he has seen excessive lobe wear after a season of racing on some of the motors he tore apart. I have my engine rebuilt to the L78 Specs. I know Competition Cams makes a cam that has the GM L78 grind specs which is a solid lifter cam, which is what I used. I can dig into my paperwork and get the part number if you would like, don't know it off the top of my head. This cam works very well in my motor!!

Rich https://www.yenko.net/ubbthreads/imag...ns/burnout.gif

Re: L78 motor cam opinion's
 

Jason;

First, the part number you quoted is a Comp cams, not a Crane.

Look here.

If you are running headers, that cam should work OK. If you're running stock manifolds, go back to the factory L78 grind.

Crane makes the current favored replacement.

Next, get rid of those .050" head gaskets. Unless the block has been decked, you're going to have roughly .075" quench distance, and contrary to popular belief, that will make the engine more prone to spark rattle, or "detonation." If the block has been decked, use a .039" gasket such as the Fel-Pro 8180. If it hasn't been decked, you can use an OE style .020" steel shim head gasket to keep quench distance in check.

Eric

Re: L78 motor cam opinion's
 

Thanks for the reply's the motor has been decked and I am running headers. As for the part number I am just going from what the guy I bought the motor from told me. He ran the 50 thousands head gaskets and told me all I would have to do was buy the correct 840 heads which I did, bolt them on and go. But since the motor is out I am going to go threw it jus to be safe! The motor has very little time on it from what he told me. Any way's thanks for all the info.

Jason

Re: L78 motor cam opinion's
 

We have a stock L78 with headers and it works fine on 91-94 octane gas. The 4 speed and 4.10 gears also keep it from lugging down and pinging. The L78 cam is nice for the street, is gentle on the valve train, yet makes decent power
.

Re: L78 motor cam opinion's
 

Watch out for cams not made in the US, I know a few friends that have had to replace cams in new motors lately from a faulty cam made over seas. Seems the cams were eaten beacuse of softer metal than needed to be used with the hipo springs and high lift, but they were told with roller lifters that problem would go away.

Re: L78 motor cam opinion's
 

Rich
I would second the thought about the Competition Cams blueprint grind for the original L78 chev cam
I asked the same questions a year ago (just rebuilt my stock bore L78 out of my 1968 L78 Nova in Jan 07)
Have about 500 miles on it now-it is just getting to the point where I am going to start running it hard(haven't went over 4200 rpms yet) great performer, idler, etc
My 2 cents
Ty

Re: L78 motor cam opinion's
 

Ty, yes it is a great cam.. I really like it. I have had the motor done now for about 6 years and put roughly 6 thousand miles on her cruisin around town and it's been great!! One thing I would HIGHLY RECOMMEND to you is now that the motor is just about at/past it's break in point is to start running AMSOIL 20W50 full synthetic severe duty racing oil. I use it and I think it is awesome. I have noticed that my solid lifter valve train is less noisy using this oil. You can also leave it in the engine for a couple seasons if your not driving the car much.. It will not collect moisture either. I know there have been many discussions here on the board regarding motor oils and I'm sure some guys will disagree with me, but I think this stuff is "THE BOMB". It also offers excellent engine wear protection!! Just some "food for thought". Good luck with the new engine!! https://www.yenko.net/ubbthreads/imag...ins/3gears.gif https://www.yenko.net/ubbthreads/imag...ins/3gears.gif https://www.yenko.net/ubbthreads/imag...ins/3gears.gif

Rich

Re: L78 motor cam opinion's
 

I would advise *against* the Comp L78 blueprint cam...the Crane/GM unit is the one you want...trust me, all of us in Pure Stock have been there, done that...you need to sit down with all of your engine specs and figure out your true compression, and that will tell you where you centerline at.

Re: L78 motor cam opinion's
 

If you,ve got new heads..it's good insurance to put NEW springs and keepers on now. Almost lost my engine last year when an exhaust spring broke. I was lucky it didn't drop down.
Martin

Re: L78 motor cam opinion's
 

Joel...there was a large thread about modern engine oil and cam break in a while back...forgot what compound is missing but its needed to help break cam in.

Re: L78 motor cam opinion's
 

I think it is Zinc

Re: L78 motor cam opinion's
 

It is Zinc. I have a solid cam from Bullet in my L78 and they sugested I use Brad Penn oil in my motor because it has the Zinc still in it. Its a Green oil same as the old Kendall oils. Here is the link

www.bradpennracing.com

Re: L78 motor cam opinion's
 

Or, you could stop by your GM dealer and get some GM EOS...

Re: L78 motor cam opinion's
 

[ QUOTE ]
I would advise *against* the Comp L78 blueprint cam...the Crane/GM unit is the one you want...trust me, all of us in Pure Stock have been there, done that....

[/ QUOTE ]

Ditto that! I'm living proof https://www.yenko.net/ubbthreads/imag...mlins/grin.gif

Re: L78 motor cam opinion's
 

Suppsedly the EOS is done being produced, stop by your local GM dealer and clean'em out

Re: L78 motor cam opinion's
 

Rob & Marlin why is the Crane Cam better than the Competition L78 Grind?? Have you guys had negative experiences with Comp. Cams??

Rich

Re: L78 motor cam opinion's
 

I have not had a Comp Cam go bad on me, but simply like the Crane better because they are blueprint versions of the originals.

Re: L78 motor cam opinion's
 

I know about a half dozen guys in Pure Stock that tried the Comp blueprint cam but switched to a Crane and the car picked up...and I believe one guy lost some lobes on a Comp piece? I swtiched over from a Melling blueprint cam that ended up going south...that Crane/GM cam will make power, trust me.

Re: L78 motor cam opinion's
 

The Jackass that posted a while ago
Ya know, I was just reading about the synthetic oil, and then you thoughts on the cam-I actually installed the CraneGM cam-I went back and forth and the machine shop and my mechanic convinced me to go with the crane Cam/valve train(just check my invoice)
Anyhow, would love to hear more thoughts on the synthetic option-have never used it ever and have owned more cars than my wife wishes to admit
Ty

Re: L78 motor cam opinion's
 

No synthetic in the older motors. The oil does seem to find a little more leaks because of the non-machined surfaces. JMO Rotella-T, Brad Penn Valvoline and that Chevron version is very good oil with still some Zinc added. The oil thing has been gone back and forth forever. The main thing I can see is just make sure you have oil in your motor. That is probably the most important step! https://www.yenko.net/ubbthreads/imag...ins/3gears.gif