The information I can gather just doesn't look right and is incomplete. The search feature for the board isn't working, and I am sure I have seen someone giving the specs for the L48...if they have it handy then sure would help to see them:

My 1975 Overhaul suppliment indicates the Lobe Lift (I/E) is .3000/.3070 and a journal diameter of 1.8682-1.8692...ok, the journal diameter isn't that important since I'll be getting new cam bearings anyway.

The funny thing is that somewhere I must have found a different spec cause I wrote on a piece of paper that the Lobe Lift (I/E) is .260/.2733.

Anyway, I did a ballpark measurement with a vernial caliper on the lobe at it's highest point and subtracted the lob at it's lowest point (This would be exactly the Lobe Lift for a 180º duration...but I think duration is something like 260º @.002). I got a calculated Lobe Lift of .259/.273. I mean isn't this weird?!?! I can't figure out where I got the .260/.2733 spec from.

Well, I also would like to see the duration and seperation numbers cause I don't really see any cam manufacturers selling an "L48" cam...they just have the grind numbers, so I'm totally unable to select a proper replacement without just blindly ordering an OEM replacement from Kragen/Checker/Schucks...which I don't want to do cause they will just give me some cheap clevite cam. I am thinking the Sealed Power cams would be trustworthy though since the parent company is Federal Mogul who has been producing quality parts for like half a century. Any opinions? Keep in mind that I am happy with the cam profile and want an exact replacement so that the number's matching block stays in one piece.

 

The specs on a stock L48 cam are
280/288 duration advertised
195/202@.050
112deg lobe center
.390/.410 valve lift
.260/.273 lobe lift

 

Why are you going to stick with the stock L48 cam specs. The modern grind cams are so much more advanced than the old style cams. You can step up a little in the duration and lift without hurting the drivability. It will probably have more drivability than the stock cam. You can leave everything else stock just step up to a slightly better cam for a little more performanced.

 

Thanks for the specs...now it makes sense.

The main reason is that I drive my vette hard. I've already broken a spindle and ripped up my tranny and destroyed a heavy duty rear end. Believe me...200HP at the rear is enough power for me to have fun. My main concern is to keep my engine healthy. It's a number's matching original engine...in fact it appears that I'm the first to open it up. With this in mind I want to keep it in original condition. The only thing I am doing at this point is cleaning everything up and putting it back together. The reason for the engine rebuild is to stop the oil leaks...both internally and externally. The leak is getting the underside dirty and it's getting a pain to crawl under there every month and scrub it down. :mad

When it comes time for more power then I'm not going to putter around with a small block. I'll just buy a 4-bolt main 454 and add a kevlar shield around the driver's cockpit of some junky vette that I can pick up cheap so I can throw in a magnum 320 in it and see if I can remove any old parts the easy way! :D

 

Okay R&R my corvette by the numbers book (by Colvin) says a 1975 165hp motor used a #3896929 - normally called the "929". the specs are not much different than your as: lift at valve is .390Int/.410Exh which is 0.260Int/0.273Exh for the lobes. Full duration is 310*Int/320*Exh. And the identifying casting symbol is a "Horizontal Diamond" just behind the fuel pump lobe.
I think if your running stock exhaust this is a good choice. In fact without headers I would go shorter to 270* max duration and run 1.6 rockers for more low-end power. You may not rev much over 5,000 rpm but low-end torque and power will be higher and your engine will live forever while totally streetable/emissions legal.
I would have saved lots time and lots'a lots'a money if I had stayed with a short cam and not installed headers. I am glad I changed cams though as my #4 Exh lobe was wiped nearly round - and the car was a real dog too.
I don't know why GM parts direct does not sell this cam? But Crane sells it as a "blueprint cam" #968711 for $106 through PAW. PAW also sells a "stock cam" #M77-229-1274 for only $50 but do not list the specs so you would have to contact them to verify (also measure upon receipt). Always use new lifters too - PAW-817 for $50. Scoggin Dickey (www.sdpc2000.com) however does sell this cam for $125 (#CC12-105-3) or with lifters for $185 (CCCL12-105-3).
Hope this helps. cardo0 :D

 

Oh yeah, thanks man. I was wondering where the 310/320 came from. Also thanks for the part #'s. A friend of mine just recommended getting the parts from PAW. But, as you pointed out Scoggin Dickey might have the best buy with $185 for both a cam with documented specs and lifters. I was currently looking at paying $300 at Kragen for a Sealed Power cam, lifter, and timing set...obviously way too much for the market...thank god for the internet and CorvetteForum.com

 

GM sell that cam in a cam/lifter kit under part number 12364051. I believe it sells for around $125.00 for the kit.

Pete

 

Rock,
Our L48's (74 and 75) are some of the whimpiest motors out there, but I like to keep mine all stock. However, I replaced my cam with a COMP 260H, and I really like the throatyand lopey idle and improved performance. I chose the 260H because it allowed me to reuse my existing springs, and didn't have to make any other adjustments. Car sounds and drives great! Reasonable price, too (got it thru Jegs). Something to consider....

 

Hmm, I just noticed that Jegs online catalog lists this identical cam for $99.99 (it was $95.99 in my may/jun 02 catalog). Eckler's Fall/Winter 01 catalog lists this same cam for $119.95. I'm thinking Jegs could get my money for this rebuild. I'll have to walk down to the local stores and buy them a beer so they can drink their unemployment away.

 

kenko74:
I'm curious as to the specs of the CC 260H cam, specifically the lift, duration @ .050" lift, and the Lobe Separation Angle.
Am considering a cam up-grade for my stock ECM '82 Cross-Fire, and am under impression I need to stay below 218* @ .050", and 113*+ on the LSA to keep the 'puter happy.
I think the 268H is something like 450" lift/ 224*+ @ .050" lift/110/112* LSA;
a bit too-much (for the ECM), but the 260H just might do the trick!

Thanks in advance, GLEN!!!

 

The Comp 260h is a good mild performance cam, I'd suggest staying away from the Crane "Blue-Print" 350/350 cam, it is an ancient grind that is designed to create max hp at 5000+ rpm. It was hot schiznits in 1965, it can't compete now. Your low end torque will suffer.
Another good choice is the Comp XE256, for good low end torque and more hp than your L48 cam. It is a more modern designed cam than the Comp 260h.

 

Glens,
Since you asked, here's what came on my spec sheet for the COMP 260H-10 (I don't know what most of this means....):

Gross valve lift: .44 (both intake and exhaust)
Duration at .006 tappet lift 260 (both intake and exhaust)
valve timing at .006 int 24 BTDC, 56 ABDC
valve timing at .006 Exh 64 BBDC, 16 ATDC
For a cam installed at 106 intake centerline
Duration at .050, 212 (both intake ane exhaust)
Lobe lift .2933 (both intake and exhaust)
lobe seperation 110

Hope this helps....

:cheers: