My cam needs to be replaced due to wear on the last lobe. My engine is numbers matching, so I want to go back with the stock cam. It seems like a Melling is a good option, but I can't figure out whether to get the 22100 or the 22127. Which one is suggested? David Vizard's Chevy Big Blocks book has explained so much about cams, very helpful. I learned that it is almost impossible to compare cam specs from two different brands due to the various ways duration is measured. The stock cam seems to have: 465/485 lift and 214/218 duration @.050.; LSA 114°.
OR
Duration at .050-inch lift: 236° (Intake) / 242° (Exhaust), Lift: .521-inch (Intake) / .540-inch (Exhaust) with 1.6:1 rocker ratio, 288° (Intake) / 294° (Exhaust), Lift: .521-inch (Intake) / .540-inch (Exhaust) with 1.6:1 rocker ratio, Lobe Separation Angle: Typically 106 degrees
Does anyone know which of the above is correct?

22100: Camshaft, Hydraulic Flat Tappet, 271/281 Advertised Duration, .398/.430 in. Lift, Chevy, Big Block
22127: Camshaft, Hydraulic Flat Tappet, 261/272 Advertised Duration, .439/.465 in. Lift, Chevy, Big Block
As you can see, none of the specs line up, very confusing.

Which Melling cam should I get? I there another brand that would be better?
What else is usually replaced: lifters, timing chain, anything else? Will I need valve springs since I am going back with stock parts?

The engine appears to have been overhauled at some point because the cross hatching is still visible and in good shape. Considering that, should I have the heads done?

I have so many questions...
Thanks, Rick

 

You must replace the lifters you should be better.off changing the springs. Not replacing a timing chain is stupid.

 

Thanks, just what I needed to understand.

 

The first set of numbers is correct everything after is not the 427/390.
https://www.corvetteforum.com/forums...cam-specs.html

 

How about something a little more aggressive
https://www.compcams.com/nostalgia-p...k-396-454.html

 

You MUST replace flat tappet lifters each time flat tappet camshaft is replaced or reground. Not necessarily so with roller cams-roller lifters

Melling has been a good source. But you might be better-served by consulting a real cam pro.

Perhaps also consider a solid lifter cam; Using solid lifters which have optionl EDM lube hole in face of lifters: greatly reduces flat tappet failures (although only available in solids).

Mike Jones
Jones Cam Designs
7859 Commerce Dr, Denver, NC 28037
(704) 489-2449
http://jonescams.com/
same gent owns & operates forum Speed-Talk dot com

 

106 LSA would be a bit choppy. Mike jones should be able to steer you in the right direction.
And it is true the same specs from different grinders will perform differently. Sometimes a fairly sizeable difference.
I will point out most cam grinders farm out the big sellers to oem grinders and the quality can be sketchy. I had my cam ground by Racer Brown in Baltimore. I never got a bad cam from them. Mike Jones would probably be a good choice.

 

Who is doing the work? Engine being torn down for a full overhaul?

Mike Jones can supply a custom cam and lifter solution that would be trustworthy. I have one of his custom grinds and would buy one again when I need one. I do not trust just anybody to specify and manufacture a durable cam/ lifter setup these days. Too much junk out there in my opinion. All Mike does is provide cams and lifters all day, every day. It costs a little bit more but you can sleep well at night knowing it will run great and not just wipe out during the break-in.

 

Rick;
Cam selection is indeed confusing.
And you are correct you absolutely cannot use advertised duration numbers to compare cams. Every mfgr measures this differently including GM. They are almost irrelevant. However you can use duration numbers at .050" lift to compare. They all use the same measuring standard there. Lobe center also matters a lot. Lift is what it is.

The three cams you mentioned are all over the map.
Crane used to make a blue-printed duplicate of your cam. I think it is still available today. It was the closest match anywhere.
It is finding a quality lifter I would be most concerned with.



BTW I always use printed cam manufacturers information.
So you would want a cam that has 214* duration @ .050,and 115* lobe separation. Hydraulic lifter. Anything with those specs would be virtually indistingushable from the stock specs. 218* on exhaust helps a little. This is a mild cam. It is all done by 5000 rpm.

You could easily go a couple degrees larger on this duration spec, and gain 10-20-25 HP. But it is all over 4000 rpm. For a lot of people this is irrelevant and a stock cam is fine. But only go 5* over to say 219*, or the engine starts to act differently. Many buyers do not care if the cam is upgraded a little bit, the factory ones are pretty mild. But they will care if it runs rough. Keep the cam specs with the car, especially if you upgrade it. It IS the heart of the engine. There are literally 1000 cams out there you could choose from, but if you stay in the 214-219* range, you'll be fine. But keep the lobe center wide, 112-115*, or it will run different. Both of those Melling cams are milder than that. Just focus on those three numbers, and you can ignore the rest of the confusing cam info.

You mentioned 236* cam above, that would be very rowdy. Even the TriPower 435 HP L71 had a smaller cam than that. This is a Hydraulic version of the L71/72/LS6 cam: With a 229* intake. I doubt you would want to change yours that much, but it is still very driveable in a 427, but the idle vacuum is lower, and you would need to tune the carb & distributor some for it to run just right. That is 14* larger than your cam! It will rev 1000+ rpm higher.


What ever you do I would suggest you do not buy a cam from Summit or Jegs, or a Melling. There are considerable differences in cam & lifter metalurgy these days, and some combinations just do not hold up. They wipe lobes. It is the quality of the lifters that gets talked about the most these days, or the lack thereof. You need an expert. There are several out there.

A hydraulic lifter cam can certainly survive these days, but you must use the right parts, and you must break it in properly.

Mike Jones is likely the premier cam grinder in the country, he will give you a stock cam or a slight upgrade, with excellent quality materials. His advice is like listening to the "Master" There are other experts out there, just do your research and choose wisely, before you take their advice.

Any mechanic can put a cam in your car. But the days are long gone when most knew how to install a flat tappet cam without a lobe failure. Choose wisely. Check references, history.

Jebbysan on this forum, has an excellent start-up / break-in procedure. This MUST to be followed for hydraulic cams. You must visibly watch the lifters spin, while rotating the crank, BEFORE you even start the engine. You must do everything you can to tune the engine, so that it starts INSTANTLY, and goes IMMEDIATELY to 2000 rpm. Do all this and it should last. Extended cranking, multiple starts, or idling, on the FIRST start, kills cam lobes.

 

Thanks so much! You have helped me focus on the important specs, which is what I needed to know. I really appreciate it. I will read through all the links you sent. After getting Mike Jones referred by everyone, that is who I will use to grind my cam. I will update everyone as the build goes on.


Rick

 

First off....the cams you listed Mr. Rick from Melling are measuring lift and duration @ 1.6 rocker ratio. Big Blocks are 1.7....so none of that information is correct. Knowing that....the duration is still in the right area....

Having owned a 69' 427/400.....the stock cam is absolutely a joke....and would be a mild performance cam for a 350....my 427 had a Comp 268H in it when I bought it and it was a little on the mild side....but it ran very good....pulled hard.....

For street Big Blocks with flat tappets....I like the ".544" cams I have been using since the 90's....there are two....one has a little more overlap....the smaller overlap is where I would have you....they are in the blue circle:


The large oval port needs to breathe....so let it breathe.....but going anymore will do nothing as you have the terribly restrictive stock exhaust on your car....

You may need to change the metering rods on the secondaries of the Q-Jet.....add a little timing....that's it.....but you will not believe the performance increase....

Jebby

 

Just spoke with Mike Jones and I ordered his recommendation:
Intake 212 .510
Exhaust 216 .519
LSA 112
5000 rpm
Thanks to everyone for your advice and help.

Rick

 

wise course of action

 

Great choice!

That is definately not a typical hot-rod cam.
Mike's cams have less overlap than most, and that gives a smoother idle, with more vacuum, crisper throttle, more efficient, etc.
But he uses some really innovative lobe shape designs that few others do.
So it is really hard to compare his cams to others.

I will bet he said it would idle smoother than the stock cam, and make more power too.
My guess is you would have to add roughly 5* to it to compare it to the power level of other cams.
(It's the duration at .200, 300 & .400 that really predicts power, and few people publish those #s)
So that 212/216 becomes a 217/221, power wise, to let you compare it to typical cams.
Right in the zone I thought you would like.
So definately a little stronger than the 214/218* OEM cam.
But with the lower overlap it should pull hard from idle!
You will not have to wait until 2500rpm like the typical 229* hot rod, 6000 rpm performance cam.
It is a good 10* smaller than those.
And it will like mild rear gears.

Win-win!

Now use whatever lifter he recommended, and get a start-up procedure from him.
If he does not give you one, you can't go wrong with Jebby's above.