if your really looking to go with an old single pattern 268h grind I have a comp 268h cam with matching lifters with about 500miles on it before I pulled it for something better.... Id part with it for $150... just an option.. To be clear this is the old grind 218/218 with .454.454 lift im talking about not the more modern 268 xe dual pattern cam..

 

Guaranteed a cam with 60* of overlap combined with a CR of 7.8:1 will be a complete turd below 3500 RPM. And not too impressive above that.
To each his own.

 

The L82 cam was essentially the L46 cam from the 60s designed for an 11:1 CR motor running leaded fuel. The bottom end in a SMOG-era L82 was already pretty soggy even with the extra compression and the 1800 rpm stall TC vs. the 1,650 of an auto L48.
Definitely don't put an L82 cam in an L48... Don't even put one in an L82...


Adam

 

FYI....the 268H cam was marketed by Comp in the early 80's (I think 1983) as a "fix" for low compression L-48 engines......it was literally design for the L-48 and all other 350's with the dished piston and 76cc chamber.......the ads in Hot Rod magazine back then even said it......it was extremely popular with the return of the Z/28 in 77'......I think by 1985, 50% of every 77-81 Z/28's had a 268H cam in it......
It was designed to let the engine breath a ****-ton better without dumping the DCR in the toilet.......and it worked. Look up old Hot Rod articles about the Goodwrench 350 buildup......the cam alone was worth 55hp with little loss of low end torque...(albeit the long tube headers they put on it covered for that)......
I broke in three flat tappet cams last year......all three with the "Z/28" Elgin spring......all three were fine! Attention to detail is the order of the day.....it is all about getting those lifters to spin right away!!! I don't even go 30 minutes.....I am at 20 minutes now and I even had one that I had to shut down at the 10 minute mark due to a cooling leak.......fired back up, ran 10 more minutes and Mui Bueno......
Leigh is right about there being a LOT of opinions......and that is fine....but when it comes to stuff like flat tappet cam break-in.....there is only one way that works, right? Proof is always in the pudding.......there are so many little things I do to make sure the engine fires immediately...and that the lifters spin immediately.......and I believe the first minute of firing a flat tappet determines the outcome........
There is more nonsense and fear mongering about flat tappet cams now that it is no wonder the novice don't want to mess with them........
I haven't wiped a lobe in 18 years........and I would say I have broke in 30-40 flat tappet cams since then....maybe more.
My "tricks":

1) Liberal application of Moly Paste on each cam lobe......
2) When installing each lifter (DRY!) a light coat of oil and a dab of moly on the foot......insert the lifter and spin it with your fingers or other means.....lift straight up on it and it should fall back down itself......spin freely and easily with your fingers......
3) Priming the dry lifters so that each lifter plunger is in the right position to open the valve right away.......don't EVER soak lifters in oil before install.....this will hold the valves open during the first few revolutions and hinder the engine from starting while the plungers find their sweet spot......
4) The firing order method of valve lash at 1/2 from zero lash......there is a lot of opinion here but I KNOW when I get to #2 that ALL the valves are lashed......try any other method while being distracted.....
5) Being 100% dead sure you are on #1 TDC when you install the distributor and using the inside distributor terminal to "phase" the distributor to 15 degrees initial.....so it is in an acceptable spot to fire......don't be "180 out" guy.....
6) On mechanical fuel pump setups......fill the bowl through the vent tube and giver a couple of squirts.....electric pumps just key on and check for pressure and a proper functioning float ( a bad float will mean engine shutdown shortly after first start)......
7) Flavor of the week Diesel oil (15w40) and a bottle of Lucas ZDDP........
8) Fire the engine and set to 2200RPM right away........vary this a few hundred RPM each way for 20 minutes......
9) Have your timing light hooked up and ready......have an infrared gun ready nearby......the infrared gun will tell you immediately if any cylinders are not firing........check your timing at 2200RPM and it should be in the high 20's low 30's......

Jebby

 

Terrific Explanation Jebby!

 

Agree 100% with Jebby on the L82 cam. I had a 76 C3 with L82 cam and T400 trans. It was a real dog until you got into mid range . I replaced the cam with an Isky 264 Mega cam with 214 214 dur, .450 lift 108 LSA. Much, much better low and mid range power. Mechanic that did the cam swap for me was a drag racer and would only install Isky cams . He never had an Isky cam go bad.

 

If I were the thread starter I would go down a different route. I would go out and buy a Vortec Truck Engine and start there. They can be had dirt cheap. Like a couple hundred buys the whole thing. The Block is a factory Roller Cam. The thing ran its whole life with an ECM running the show the Bores are probably are still good to go. If the heads are not cracked they are some of the best nearly free heads to be had. My machinist told me to go this route as they are machined better with more modern tooling than the old 2 piece seal blocks. Put it on an engine stand and learn everything about building a SBC not in the car. Having recently built one of these myself I will only use a 2 piece rear seal block for a restoration if the numbers match in the future. If your building a SBC on the cheap just the cost of aftermarket roller lifters alone makes this a better choice.