As the title above states, I need some opinions on the ( 3 ) cam's below. I'll start by giving you some info on my car first.

Car is a 2001 SS that I am currently building a Iron Block 408. Compression is upwards of 11.5 to one.

Intake- Will either be one of the following Fast 90 with a NW 90 ( I already have this one, trying to sell it though ) or a Ported Fast 102 matched to my new heads.

Heads- are CNC ported TFS 235's with a little work done to them.
All forged bottom end, so it should hold up.

Trans- is a 4160E, with a Yank 3600,rear gear will be 3:73.

Exhaust- Will be TSP 1 7/8" SS with a 3" ORY connected to a Magnaflow Catback.

My car is not a daily driver so driving it everyday is not an issue. With that said I am looking for a good all around street car, that will make great power, be valve train freindly, and fun to drive. I have heard that the 408 will have good torque. This car will not be a weekend drag strip warrior, however I may take it to the strip every now and then, and or compete in a little local street racing. Not planning on any juice, ( at the moment ).

I have spoken with ( 3 ) guys and below are their recomendation's concerning camshafts. I was wanting to see what the Tech community thought about them good and or bad. I was told that the higher duration would deliver more all out power numbers but suffer some low end torque, and the lower duration would deliver more all out torque but suffer some power numbers.

1. 243/250 .624"/.615" 112+5 Recomended by a Tech sponser ( no names mentioned ) dont know what the lobe design is it's supposibly a custom cam. Pros/Cons

2. 239/250 .621"/.595" 113+2 Recomended by a Tech sponser ( no names mentioned ) dont know what the lobe design is it's supposibly a custom cam. Pros/Cons

3. 232/238 .625"/.625" 113+4 or 113+4 Recomended by the guy that is completing my short block assembly. dont know what the lobe design is it's supposibly a custom cam. Pros/Cons

4. 235/242 Lift .620/.610 113.0 +2 Lsr on the intake, and a Lxl on the exhaust, Already Have this one new in the box. but was told that this lobe design is a little on the ragged edge. Pros/Cons

Any and all help would be greatly appreciated as it is getting time for me to pull the trigger on the new cam, as the shortblock is almost ready for assembly.

 

Then how do you explain the performance of the SNS Stage 2?

 

I'm no cam guru but I'll throw in my $.02

IMO number 3 is too small. You will be getting in the upper limits of dynamic compression. IVC is early for a 408 and not enough overlap.

Number 4 would be a very nice street cam. The LSR lobes aren't suppose to be too hard on valvetrain. With 12.5 degrees of overlap it would be very nice to drive in a 408.

Numbers 1 and 2 will give the most power. I'd be surprised if you noticed much difference between the two. They have similar valve events but number 1 has 4 more degrees of overlap so it would have the roughest idle and make the most power.

 

I would contact Martin @ Tick Performance. He has helped many on tech with the camshaft selection part of their build. Also, you should look into getting your converter restalled to at least a 4k and up to a 5k for better performance.

 

Choosing the right cam is a tough one for sure.

No matter who you go to for advice, they will try and sell you their cam.

I suggest calling up the most reputable person you know that builds quite a few engines and has dyno/performance proven combos.

For example: Texas Speed, they sell and build 408s all day long.

 

badazz81z28, you are correct on deciding exactly which one to go with.

I have already contacted a couple of site sponsers already. They recommended 1 & 2 however my engine assembler recomended # 3
LOL,

I was just wanting to heare from some of the guyd with current engine combo's to mine.

 

May I ask....does your builder have a lot of LS engine experience? Any references from past customers?

 

badazz81z28, The guy that is assemblying my short block for me is a very reputable, engine builder. However he mainly builds old school engines. He has built some of the LS seris engine's but mostly the older style engines. I think that is why he is reluctant towards the higher duration.

 

The majority of his engines are built and destined for the dirt track racing world. Dont get me wrong they are some of the best built engines out there, and like he said he buids them for all out torque. and not specific dyno numbers.

 

IMO, I'd run the cam you already have(#4) the 235/242 113lsa+2. If should be a good street cam in you 408.

 

When you say valvetrain friendly are you wanting to keep a single spring that will last 50k+ miles or a dual spring that lasts 20 - 25k miles? Pretty much all those cams are going to be tough on valvetrain and require a good dual spring.

Cam number 3 but on a 112.5 LSA with 109 ICL would be my choice if I had to pick one of the three. Lower duration gives more torque and the 10 degrees overlap should give a nice performance idle but still traffic friendly and the 45 IVC should be good for making power to the 6500 rpm area. If you were willing to give up idle a bit I would choose that cam with a 109 LSA + 0.

 

I concur.....

 

I've dyno tested camshafts and you literally cannot open the exhaust valve soon enough after 3500rpm.

Literally cannot open it soon enough.

The IVC event controls 75-80% of torque production. Exhaust events only affect the torque curve after peak.

Take a look at the combo Brian Tooley did for a guy the other day with TFS heads. 239/252 111+5 cam in a 6.0 made 500+rwhp and nearly 450rwtq.

Tell me again how extended exhaust duration hurts torque?

It doesn't.

If Bozzhawg feels I'm wrong I kindly ask him to share track/dyno numbers he has done cams for that prove this wrong.

Chris Frank did a 416 the other day with TFS 235's with 12 degree I/E exhaust split. That engine made 603rwhp and 530rwtq IIRC.

I did a 408 the other day with 15 degrees I/E split that made 9 more rwtq and lost no power under the curve to a cam with less split. The kicker is the old cam was dyno'd on 275 radials. New cam was on 28x10.50" ET drags. It also gained 140rwhp on a 200 shot at 7000rpm where the old cam was falling off a cliff at 6500rpm because it couldn't exhaust the cylinder at higher piston speeds. It was trying to burn spent exhaust gas over again. You can't extract energy from spent hydrocarbons. Power will never increase let alone maintain. It will plummet.

Again tell me how extended exhaust duration hurts torque production?

I ask to be proven wrong. Not argued with that's all. I can provide factual data to back all of my claims.

 

Which cam works "best" really depends on your goals. If you're looking for baby smooth idle and you really don't care how much power the engine makes, then obviously use a small cam.

However if you're spending good money on a Fast intake and aftermarket heads, then I would cam the engine for excellent overall power. There is so much misinformation and ignorance available online that it's completely overwhelming to the buyer.

A few months back I paid to have 18 cams tested back to back on a engine dyno on a complete LS3 engine, it was stock from intake to oil pan. Obviously we've done tons of camshafts and had noted lots of trends, but to dispel the myths we wanted to do the testing to know for sure.

One of the trends we had noticed was that less exhaust lift seemed to make more power and since it's easier on parts, less exhaust lift becomes a win-win, something that is rare with performance. We tested 2 cams that were both 232/236 113+4 with both having the same .62X" intake lift, the first having the same .62X" exhaust lift as the intake, and the other having .59X" exhaust lift. We had seen the lesser exhaust lift seem to make peak power easier, probably due to less float, but we were shocked when the lesser exhaust lift actually made more power everywhere.



The next test was to take the same 232/236 .62X"/.59X" 113+4 cam and simply add more exhaust duration, so we tested a 232/240 113+4, 232/244 113+4 and lastly 232/248 114+5. The last cam features the same exact intake valve events, and the same overlap as the 232/244 cam, so the ONLY difference is the EVO is 4 degrees sooner, it was changed from a 59 EVO to a 63 EVO. We changed JUST the EVO of the last cam to see what affects JUST a very early EVO event had on torque. You can see from the graph that the increased exhaust duration made more power from about 3000 rpm on up.



So for your combination I can tell you without a doubt that a 58-62 EVO will work well, a 49-51 IVC will work well, and 16-20 degrees of overlap will make more power everywhere, and still drive well if you have a good tuner.

If you go by those specs you can start to eliminate cams that are wrong for your combination.

...........................EVO.....Overlap....IVC
243/250 112+5.......62.......22.5........48.5
239/250 113+2.......60.......18.5........50.5
232/238 113+4.......56.........9..........45
235/242 113+2.......56........12.5.......48.5

The 3rd cam has a 45 IVC, which is really early IVC for a 400+ cubic inch engine with cathedral port heads. It might work with square port heads, but it's leaving a lot of power on the table

The 4th cam with a 56 EVO and only 12.5 degrees of overlap is also leaving a lot of power on the table.

I hope this helps.

 

Of what Brian posted, the 239/250 113+2 is probably what I would do for a streetable 408 that makes power everywhere.

 

Now the heavy hitter's are finally coming out. That is exactly what I was looking for actual first hand knowledge.

From what I have heard Brian you and Martin are the best in the game. I value your technical knowledge and opinions. Therefore I will be giving you a call Monday to get my cam headed south.

 

I wonder who spec'd the first two cams.



Brian when you told me about your dyno test and the results with EVO I took them with a grain of salt.

Alas, I decided to try some things.

Let's just say you were right as always.

 

Martin, I know you like a later IVC on 4" strokes. Is 45 too low for a 3.9" bore with a 4" stroke? Or is closer to 48 more ideal?

 

Depending on the total cubic inches, and the weight of the vehicle, rear gear, stall speed, trans used, CSA of the port at various locations, valve area, compression and what intake manifold is being used it can vary greatly.

It would depend on a lot of things Jake, but I would shoot for 44-48 on a 383 for a street car.

In an application like this, I would like to see a 46-50 IVC event as he has a 3600 stall converter.

Here is my example of how an earlier EVO does not hurt torque production.

I know this isn't a cathedral port motor, but it's a perfect example.

408, Mast small bore LS7's, Mast 4500 single plane, LPE GT21 camshaft, LS7 lifters, stock 1.8 rocker arms.

GT21 cam specs:
243/259 .691"/.702" 112+0

Valve events@.050"
9.5 IVO
53.5 IVC
61.5 EVO
17.5 EVC

27 degrees of overlap @.050"

My cam specs:
255/270 .700"/.698" 113+6

Valve events@.050"
20.5 IVO
54.5 IVC
74.0 EVO
16.0 EVC

36.5 degrees of overlap @.050"

As you can see, the IVC did not change but 1 degree later, and EVO has changed 13 degrees! In Brian's test they changed the EVO 4 degrees.

Old cam was ground on LSK lobes. New cam is a new lobe I like a lot in high rpm applications with heavy stainless valves like this one. 7800rpm on LS7 lifters and no signs of valve float with 1.8 rocker arms. Stock rockers and 3/8" push rods help a lot.

Old cam was dyno'd on Mickey Thompson 275 radials, new cam was on 28x10.50" ET drags. No torque was lost on motor anywhere with the new cam vs. old cam. Of course if it lost no power on motor it surely wouldn't lose on nitrous. Theoretically if it were dyno'd on radials both times for both cams, it would gain much more.

The slight loss in torque you see on the hit of the nitrous pull would be gone due to the radial holding its sidewall instead of the slick flattening out and losing torque. Once the slick gets some wheel speed though it grows and power loss isn't near as great.

He has since taken it to the track, and on 100hp less nitrous has matched his old E.T. of 5.56@125. He had to pedal it twice on that pass as well to keep it from going on the bumper.

Here is the motor pull:


Note no loss in torque on motor what so ever under the curve even on a tire that will eat up much more power on the dyno. Again, the slick is going to flatten out when hit hard. Just like watching a car with a slick at the drag strip launch. The tire wads up all kinds of crazy. A radial doesn't do that hardly at all. Nice soft motor pull won't do that, but you throw a 200 shot in the mix and you bet it will.



FYI 140mph on the graph is about 6500rpm and 150mph is 7000rpm. 165mph is around 7800rpm. This is a 200 shot. The gains will be even larger on more nitrous.

So, with that said and I mean this with all due respect, anyone who says something to you about camshafts and valve events, but can't supply evidence opposite to the contrary be weary of that information.

Not all statements hold true, and on a smaller motor I am more conservative with where I open the exhaust valve. On a big 4" arm motor though, it's going to have more VE than a 3.62" arm motor. This needs more time to blow the piston down on the power stroke to aid in scavenging and evacuating the cylinder.

I hope this helps with the visual in regards to how changing the exhaust valve opening event really doesn't affect anything below 3000rpm if that at all.

 

Some good info in here.