Is anybody running a Comp Extreme Energy 12-4-412-8, 212/218 cam? Your comments please. I'm running ZZ4 aluminum heads, Edelbrock Performer with stock QJ, and headers with good straight through 2 1/2 pipes. I know there are a zillion suggestions for cams that make more HP, but I want a smooth-running, dependable car that will give me a little boot in the backside when I come out of a hilly country sweeper and see a quarter mile of straightaway ahead. This is a case of "done that, been there and got the hat" but still want some fun driving. I'm an old man, and I've already run at Daytona, Sebring and Bonneville, have a 200 mile per hour club hat already, and have felt the thrill of 900 hp on the track. I just want a little more fun - - I'm not dead yet.
Dick J

 

There are some smart people here who suggest you run the 268H-10 high energy instead, which is a similar cam but 218/218. The thinking is that the ramps on the 212 intake lobes are too steep for reliability.

I have this cam, but it's not installed yet. Check out this thread:

L48 performance upgrades by the numbers - CorvetteForum - Chevrolet Corvette Forum Discussion

 

I like the cam recommendation in the thread above, but something else to look at to get more acceleration “feel” out of the car is the gearing. If you have a stick it probably has a 3.36 rear end. Going to a 3.55 or 3.70 would make a noticeable improvement.

 

I understand what you are saying and know where your head is at.

I just swapped out the cam (third time) in my 383 stroker for a custom grind from Mike Jones. I was OK with the other cams, but just not thrilled. Mike does not grind the typical rough idle, cantankerous high overlap cams. He designs an efficient custom cam to match your exact application and engine specs. I'm running a solid flat tappet grind that idles at 750 RPM, 18" of idle vacuum, kind of like a stock L-82 and will cruise in overdrive at almost any engine RPM from 1000 RPM and up. It's almost as smooth as my 2010 Camaro just driving around. This is what I asked for and i got it in spades. 10.7 CR, custom Lars built Quadrajet, and a TKX 5 speed OD trans. Oh yeah, If I punch it, it rips!

His prices are not much more than a cam from the big names but NONE of those companies can sell you a cam that performs like the ones Mike makes. Those other companies honestly do not make any cams like this. I know I sound like a commercial but it really is true. Anything from hydraulic flat tappet to roller grinds. Only the highest quality cores and best lifters available. I am sold.

 

Hello,

I had an engine built for my 1972 350 coupe early last year. I wanted significantly more horsepower than the stock 200, but just as important I wanted the engine to have more low and mid range grunt with as smooth an idle as possible. I don't race the car ever, but I wanted it to be more responsive in the rpm range I drive in. Some of the items I had installed were new 64cc aluminum heads, hypereutectic aluminum flat top pistons, roller tip rockers, Johnson-Isky lifters, a retro hydraulic roller camshaft and an Edelbrock aluminum performer intake manifold. The car also has long tube ceramic coated headers. The Comp Cam retro hydraulic roller camshaft recommended and installed was the 12-412-8. The car idles very smoothly and has plenty of get up and go. I am very pleased with the build. I too am a senior citizen at 66 years old and my racing days are over, but I enjoy occasional spirited driving I do. Attached is a picture of my engine installed.

 

Miccar
standard bore and stroke? stock rods? Tell us more about rotating mods as I am looking in to improvements. what pushed you to roller set up?
tia

 

I think that is a solid cam choice for what you want. Although im not running that specific cam, my cam is almost the same lift and just a little more duration(bout 10 more) and it has zero issues running/idling and pulls hard. I do have a mechanical Holley carb tho not a QJ. Only reason I mention that is I’ve heard that Qjets can be finicky with cams that affect vacuum, and I’m have no idea when that starts to occur. 12”? 15”? No idea. My c3 only had its Qjet for its drive home.

 

My car had a 350 replacement truck engine that was already bored 040 over in it and I didn't want to use it after having it bored 060 over. The engine builder / machine shop had a nice low mileage 350 engine from a 1970 Corvette that had never been touched. They bored it 030 and used that block. The block was degreased, magnafluxed, decked and line honed. The original connecting rods were resized and used. In addition to the work noted in my original post some of the other work they performed was installing new Ferrea valves, Manley pushrods, Clevite bearings, Melling oil pump and pickup, Cloyes timing set and all ARP bolts. They also purchased bare 64cc aluminum heads and did a complete valve job honing the exhaust guides and setting the spring heights. As for going with the hydraulic roller cam, I was assured that if I went with a regular hydraulic cam it would be broken in properly and I would not have future issues with the cam lobes if I used the oil that contained zinc. They have built many engines for classic car restorations, crate engines, circle track, drag racing and truck and tractor pulling events and are well regarded so I felt I could trust them. The money wasn't as much an issue for me as was performance and long-term reliability. I also didn't want to purchase special oil containing zinc and I liked that the hydraulic roller cam setup gave improved performance. I decided, therefore, to build the engine with a retro hydraulic roller cam. The car runs very well and I am pleased with performance and the quality of the work that was done.

 

What cam are you running now ??

 

Comp Cams retro hydraulic roller 12-412-8. RPM range 1200-5200. Strong low and mid range.

 

Thanks Miccar, my ? was for the OP (DickJ)

 

My engine is similar to the OPs, so I was curious about the Mike Jones option. I sent them my engine specs and a few comments and got quick responses from them. What I told them was:

• 1977 L48 350, original bottom end with the 18 cc dish pistons
• Trickflow DH175 heads
• Edelbrock Performer
• Rebuilt and tuned Q-jet
• Rebuilt and curved distributor
• Flowtech 1.625" x 3" long-tube headers and true 2.1/2" exhaust
• Looking for 5,500 max rpm, peak HP @ 5,000 rpm, and broad street torque

Here's what they came back with:

• Cam # SBC, H65295-66299-110
• 204/208 @ 0.050" duration
• 0.295"/0.299" lobe lift
• 0.442"/0.448" valve lift
• 110 LSA
• Intake valve closes 56 degrees ABDC (0.006")
• Estimated 350 HP @ 5,100 rpm and 380 ft-lbs @ 3,500 rpm
• "It will pull hard from idle to 5,500 rpm"
• Cam is $338, lifters are $179.

It seems a little light on duration, but if the power numbers are good, it's about what I was expecting from the Comp Cams 268H that I already bought. Mulling over the exchange....

 

From my experience, Mike Jones numbers do not match up to other cam companies numbers. First of all, Mike's are rated at actual seat timing not .006", .004" or whatever the other guys rate their cams at. Also, the lobe center spec creates the overlap event. With other cam profiles, you have a basic idea of how lopey the idle will be from experience, but with Mike you can just throw that out the window. My Howards 112 LSA cam I ran first had lopey idle, less duration spec and wider lobe separation than the 110 LSA with more duration Mile Jones ground cam. Most people would assume a higher 850 RPM, lopier idle with tighter LSA and more duration but it didn't happen.....it was the opposite....I got a 750 RPM smooth idle. I was very surprised. It's all in the grind.

 

I ran a bigger hydraulic roller cam with 520 lift/ 280 duration and solid roller lifters. It was great and I loved it. But I had bought needle bearing lifters that exploded and littered my engine and the resulting mess blew a head gasket as well....Your cam will be mild with your duration numbers but should be better than stock and have good vacuum for accessories. I would invest in high dollar lifters with bushed bearings and not needle bearings.....buy once, cry once.....

 

Got any suggestions for this lifter style?

Yea, the duration numbers seem mild, about ten degrees above the stock wimpy cam, so I'm not sold yet. But I found a few examples of people that replaced their cams with similar duration MJ cams and got surprisingly good increases in HP. I've read everything I can find on getting the most out of the stock L48 bottom end, if this MJ cam with my other pieces gets 350/380, I'd be happy with that. Without going to flat-top pistons to fix the quench problem, upgrading rods, etc., those numbers are as good as I've seen from any other predictions.

 

If you buy the cam and lifters from Mike, you get a warranty. Otherwise you don't.

His break-in instructions are more involved as well.

 

Several of you asked for more info on what I'm running now. Good question. The numbers check out to be a 1971 block cast in St Catherines, Canada. I am assuming it has dished pistons, but you know what assuming does! It feels like about 275 HP right now. It currently has headers and a good true dual 2 1/2 exhaust system. Auto transmission. I am installing the roller Comp Cam noted, new push rods, roller rockers, ZZ-4 heads and an Edelbrock Performer intake manifold. I'm hoping for 350-375 HP. DickJ