I got my cam from Jones. He nailed the numbers that I wanted exactly! I know it is just math, but very happy with his service. Dyno loved the cam. No driving yet but soon! I have dealt with Mamo also. He did my heads and intake. Would trust his insight as well. Those are two of the best around.

 

Just got response from Mike Jones, read below. I am a bit surprised at the 112 LSA reommendation,.....and do not quite understand it, given I was specific about low end torque. So I asked him why, and his response is below as well. I think the duration is where it needs to be, thought it might be better even more single pattern. The lift numbers with 1.6 ratio will be .544 which is what I expected. Everything I read says AFR heads, especially the Comp head, like single pattern and lots of lift.

Here's what I recommend.
Cam# SBC/Cst, HR70340-71340-112
224/228 @.050'
.340"/.340" Lobe Lift
112 LSA
Steel Billet, w/iron gear

I went with a short seat duration(272/276), and the 112 LSA, with an Intake Centerline of 108. The short seat duration and 108 ICL will make plenty of low-end power, and the 112 LSA will keep the overlap down, so you won't run into any reversion issues during part-throttle driving.

Still waiting for Tony Mamo and Comp to respond. Wish I knew what Straub would provide, but he refuses to give me the spec's until I send him money. I just sent him an email asking him one more time if he could provide me with what I need to make a good decision. It seems like a reasonable request to me.

 

Just a comment on the 112 LSA issue. I have a Crower hyd roller in my 383 that was originally designed for 108 LSA. I was talking to a Crower tech and he mentioned that for $30 they would change it to 112. I wanted that because it supposedly flattens the torque curve and provides better vacuum at idle and low rpms - mainly for headlight and brakes operation. I'm very happy with the way it worked out.

 

Comp Cams has responded with their cam recommendation. Its one of their Magnum Cams, 230 at 0.050, .560 lift, single pattern 110 LSA. I like most of it except the 230.......I think it needs to be down in low to mid .200, i.e. 224-225, with same lift. 110 LSA is going to be a middle of the road cam, and very popular.

Still waiting for Tony Mamo, and hope Chris Straub decides to tell me what he would sell me. I am also waiting for Crower.

 

Thanks BK. My 350 has a 110 LSA Comp Cam, and the headlights go up as fast as they can, but I have 18 inch vacuum with my cam. As for the brakes, they work. I wish I would have just put on non-power brakes on the car, as it would be fine with me. I have converted the car from factory power steering to manual steering, and it now drives like a sports car should. So, my main concern with the 112 LSA is that everything I read says it moves the torque up higher in the RPM band, and back to back tests with cam LSA across the range from 108 to 112, the best torque cam for down low is the 108.......but yes, it comes with low vacuum.

 

Tighter lsa narrows the power band and causes more overlap with lower vacuum, as long as you have good compression to work with wider lsa cams can be a good thing. Single pattern cams can work but regardles of how good the exhaust port in the head works you better have a superb exhaust system or better yet none like a race car. I agree with you the comp cam has to much duration , .050 230 in a hydraulic is more like a solid cam of .050 238.

 

No cam designer worth his salt is going to provide all, repeat ALL, the specs to a one-time-only small customer ... even after you buy. Expecting otherwise is not reasonable.

There's so much more to it than a ramp here & there plus some duration & lift ... way more.

Even in amateur circle track restricted racing, where most things are closely regulated & monitored, one-off cam and carb tricks are paramount and front runners' specs are closely guarded.

You might get into a used digital cam doctor / cam profile analyzer for $3-$5 K ... then , if you knew what you were looking at, you might Begin to copy someones profile.

I know a fellow who used to drive for Elliott ... USED to ... driver sneaked a look inside Ernie Elliott's carb ... Ernie caught him and driver got the bum's rush ... quickly went from sugar to sh7t.

 

LSA and Advertised Duration Why?

This all came about during the Cam Wars of the 50's and 60's. Crane, Isky, Erson, Streigal, Winfield, all used LSA a marketing tool as it was a single number group....simple and easy to list in a catalog. Valve events would have taken up too much time and be to hard to explain. LSA was chosen because it was simple number.

Wider LSA... As cams grew, so did the need for fly cutting pistons. A very well known cam grinder and pioneer in this industry that has left us, once told me that the only reason he put stuff on wide LSA's because he was tired of listening to engine builders complain about having to fly cut pistons. So the wider LSA for him was to appease the customer, not a gain.

LSA is what it is. It is a sum of numbers. The combinations Demand and Supply will determine what area of lobe is needed, how much lift is needed, and when the valves need to open and shut. We have been marketed to that Wider does this and Narrower does this. For marketing, this simplifies the process, but there are to many variables these days to say this does this this does this. In my world, LSA does not factor into the equation, it is a sum of numbers at the end of the day.

Advertised Duration comes from the marketing/advertising of camshafts back in the day. The duration used became the duration that they Advertised the camshaft in the books. The marketing side was that some choose duration at .004 and some choose duration at .006" to be the Advertised numbers. So you had a camp that said .004" was correct and a cam that said .006" was correct. The issue was the .004" guys always had bigger "ADVERTISED" numbers and we all know that marketing to the "Bigger is Better" theory works. A "Summit" of sorts was held at the US Nationals in the 60's and result was a new number to "Advertise" / "Market" with and it was .050" Nothing magical about this number except that .050 was the same on the East coast and same on the West coast. It is just a reference point.

Someone mentioned Harold and .200" and that being important. I will take it a step forward, every point of tappet height is important; the total lobe area. Comparing .050" numbers from 1 cam to another can still get you in trouble and not tell you the truth about how a car will act. I use the example I have 2 lobes that are with .004" of lobe lift and both are 230@ .050". On paper one would think that if 2 cams were ground as single patterns with these lobes there would be no difference.....Well there would be a huge difference as one is 12 degrees larger at .200" than the other one. This one can either kill torque on a low rpm build or can keep a restricted engine hanging on in the rpm range when compared to the other lobe. If we saw 2 cams and one was 12 degrees larger at .050" we would say there was a huge difference. This is why I say you need to be very careful when comparing .050" numbers. A much better comparison is looking at .050" and .200" If these numbers are close then the lobe area is similar and you can expect similar results. Just keep in mind with lobe lifts of .375 and higher there is still the chance that there can be quite the difference.

Hope this helps explaining some of this.

 

And wouldn't it just be perfect, and a learning experience for all of us if Chris Straub would just provide the cam specifications that would make my engine perform like he suggests it should.. He could even make money at it.

 

No, not really. As he said, specs off a cam card don’t tell the whole story. Given you don’t have full profiles of the other cams, we’re all still guessing at area under the curve, ramp rates, and exact timing of valve events.

 

I'll be surprised if either Jones or Straub receive that order ... even astonished if Straub accepts it.

 

Just a reminder about vacuum solutions. You could convert your brakes to hydro-boost. Thereby, eliminating that need for vacuum but still having power brakes.

 

And btw....let's not lose sight of what the OP started out asking for and wants as opposed to what lot of people want him to do.
A torque engine that does not have to go above 5,000 rpm.
Basic cam specs provided by the reputable cam companies should fill his needs if not off the shelf, then by a reasonable ground custom cam from someone like Comp.
He is not trying to squeeze the last 10 hp out of it.
Just mho.

 

The idea LSA is just a sum of numbers is bull ****.

If it had no meaning except it is what it is "just a sum of numbers" Fuel injected motors would not seek 112 and above , NOS motors and forced injection would not have wide a LSA . And no one would bring it up when discussing the cam in those applications. IMOP and having HAD a "Straub Cam" He is full of ****.

 

He (Straub) is correct, lsa means nothing without looking at the rest of the cam specs. Just saying efi engines need 112 lsa or more without understanding the cam means nothing. My drag race bbc has 284/296 .050 duration numbers ground on a 114 lsa. That would not be a good factory efi cam. Wider lsa usually means there is less overlap which means better idle and low rpm performance if you had two cams with the same specs other then lsa. That same logic cannot be applied to all cams with the same lsa, you must look at the whole picture. The Vortec truck cam from gm in 1996 had a lsa of 111, but it is a smooth low rpm cam because it's overlap is small.

 

I could not agree more with Bmans statement above. Since I am not a cam expert, I have tried to read and learn as much as I can, and I have asked "experts"....meaning people who do it for a living. And then, there are the self proclaimed "experts" that post on forums, who can be credible, but normally they have an agenda, or simply cannot focus on the engine parameters that I want, and try to build my engine they way they want. I would like to trust the "experts", but here is why I find it difficult and a list of what some of the "experts" have said to me verbally on the phone, or emailed me, or PM'd me:

- "Expert" said GM Factory Hydraulic roller lifters have problems with swedged axles and would not be recommended. Very expensive lifters are a better choice, and surely the expert has the them to sell me. My question,.....how many GM vehicles with swedged roller axles are on the street? Is their really a problem that I need to worry about? I don't think so.
- "Expert" would not recommend buying AFR 195 Competition Port heads versus AFR 195 Street heads, not because of cost, but because the 2.08 intake valve in the comp versus 2.05 intake valve in the street will reduce the velocity. I asked the man who designed the head. Tony Mamo responded to that statement directly to me stating the increased performance and flow of the Competition head far outweighs the small (0.03 inch) intake valve size / theoretical velocity difference, and yes, in my application. There is more to that Comp head than just an intake valve size difference. I think Tony would know. He is an expert I do believe in. There is nobody who does not put AFR heads at the top of the list.
- "Expert" told me that my AFR 180 heads are too small for a 406, but then when I suggested an AFR 195 Competition head instead, it is too big because of a 0.03 inch difference in intake valve size. Yet most say 195 cc heads are too small for a 406.....so which expert am I to believe in?
- "Expert" told me there was no need to sonic test a GM factory 400 block for cracks. I was to build an engine in a factory 400 short block, that I need to run 100,000 miles, and I was not to worry. Lots of "experts" disagree with that, and surely would not suggest ignoring block testing.
- "Expert" told me that the reason I want a Holley Double Pumper carb is because I like the "engine to bog". Apparently, Holley has provided double pumper engines for what, 40 years, and they all bog. Marketing genius,......fool everyone and sell thousands of products that do not work. The reality is, any carb has to be adjusted to your specific engine, and I would have preferred that response.
- "Experts" are now saying that there is so much "super secret, only experts can know details" of a cam that normal cam specs of duration, valve lift and LSA are not enough for a 61 year old guy with a 77 Corvette, who just wants to select a cam that provides a strong torquey engine, in the 2000-5000 RPM range, with emphasis on torque on the low end of that range. Create a mystery, and provide a solution....that's good marketing. How about just a simple answer for a simple request?
- "Expert - Comp Cams" - when they suggested I use a 230 Magnum, based on MY completing their forms, I returned with stating that they are not addressing my low end torque need, and they returned saying....okay, yeah 224 is better. Why didn't they say that in the first place? My takeaway from that interaction is their recommendation is irrelevant since all it took was me talking them in to it. No credibility.

I could go on with more examples, but my point is this. On this forum, and many others that I read (Yellow Bullet, Chevelles, Nova, Speed Talk, Tri Five, etc) this subject brings up opinions that range across the scale, with "experts" proclaiming the best of anything, doesn't matter what the subject is, and you get answers exactly 180 degrees opposite of each other. I also have read all the car performance books published, including Vizards books. And I am also getting plenty of Private Messages from people who discredit the "Experts", but don't want to state it in public. So I trust little....and will come to my own conclusion as whose advice I do trust .

What I wanted in this thread, on a Corvette Technical forum, was to attempt to establish MY parameters for MY engine, and see a consensus, within a reasonable range of cam specs, i.e duration, lift and LSA that gives me a good chance of getting the right cam. Problem is, one of these "experts" will not provide those numbers, and I am to trust him, even though he does not trust me. The other biggest problem is that 90% of the people on the forums see engine performance from "drag race" perspective, not street performance in the 1500 - 4000 RPM range that I specifically, and most others, really care about.

So as Bmans said, I am just looking for the best cam for my situation, and do not care about small insignificant details that will provide a hundredth second advantage in a drag race. But I cannot even get a consensus on that simple question. Very frustrating.

Right now, I am interested in what Tony Mamo says, still waiting on Crower, and I will be calling Mike Jones, just to hear his rationale for his selection. I will be buying a cam soon from someone, and I suspect it will be in the low .200 range, small difference in intake/ exhaust duration, mid .500 lift, and who knows what LSA. That is the consensus for now. If I can tweek it a bit more, its part of the fun of it.

Thanks to all who have maturely tried to help. I enjoy the interaction. For those of you who choose to make immature comments, you are on my "Ignore List", so no longer reading anything you post.

 

If I was looking for a cam using your specs, it would be an RV/truck cam. Btw, I'm not an expert. I also agree 100% with bmans comments. You don't need to design an engine to extract its full potential unless of course you make your living from racing. Not many in here do. You just need to "average" out the advice and make choices. If the engine doesn't pull as hard as you would have liked then live with it or make changes. But you should have enough knowledge to make your choices and be satisfied with the results.

 

Take the points you have, draw them out, and connect them with a straight line. Then compare that triangle to an actual cam lobe. See the difference?

Now look at what Straub told you to do to get a better look at the actual profile. This is the difference between low definition video and 4K. The more data points, the clearer the picture. You have a triangle. The actual lobe is rounded.

It is entirely up to you which expert to trust. But here’s the deal: Straub told you how he does business. You didn’t like that, which is fine, move on. But why are you so desperate to get his recommendation? Why are you trying to goad him into making an exception for you? Do you actually trust him to give you the best cam, or are you just looking for another data point? If his recommendation came outside the specs from the others, are you still going to buy from him? If the specs are in the same ballpark, are you going to buy from him?

I have no horse in this race, and don’t know Straub at all, but it is very obvious he doesn’t win anything giving you specs at this point. Move on or, if you actually trust him, pay up.

 

Do you read what He said , "In my world, LSA does not factor into the equation, it is a sum of numbers at the end of the day"

Now take your reply to me and delete it. Because it appears as if you think I did not read what he said. Or as if I am dumb and do not realize what other aspects play a roll in a cam shaft.. Thank you

As to Straub the LSA matters it is not some random old school trick or a marketing ploy . What it is in fact to him , is a shelf grind from a supplier he see's matches a sale. And this is why he talk's that smack about LSA.

 

Flyboy,
The issue with this entire thread is some people are pushing their agendas and not yours and the fact that what you have asked for and then actually decided to build are not the same. Your contradiction in goals vs parts turns off many people that want to help you but have been chastised by you. From the start you have been pushing low RPM power, max torque at 2000 RPM and noting that you would never push the engine higher the 4000 or 5000 RPM, that was the stated goal. Fine, some knowable people tried to suggest ways to do this the best they could while pointing out the issues with such low RPM goals. Like keep the 180 AFR heads and get a cam with very short duration like 211 to 220 @.050 on the intake side. In the end you decided to go with 195 heads and a cam with intake duration near or above 220 degrees at .050. While I feel this engine will work great in you application and you will be happy, it is not what you asked for and have kept pushing people to provide you information for. Your engine with 195 heads, a dual plane performer intake, and cam timing in the 220+ range at .050 will peak torque at 4000 RPM to 4500 RPM with a HP peak in the 5500 RPM to 6000 RPM range. (Not at your stated goals)
What you are building is what most people would have suggested from the beginning for a torque build because it will be a very street friendly combination that will work very well but it will not have peak torque in the 2000 to 2500 RPM range and it will not have peak HP on the 4000 RPM range. Your stated goals vs actual parts are not in line with each other. Either your stated goals are wrong or changing or the parts selected will not acheive your goal but they will work well.