[pastry_chef]

Originally Posted by Half-Inch Stud

Opens the question of LSA! What about those 104 LSAs? is the Vizard 128 rule good & right?

Does anyone wonder why Len Caverly would make a comment like this?

For those who do not know Len.
He has his own dyno, ports heads, owns high end analysis software and competed in Engine Masters.

------
I do Pontiacs and yes a 108 cam will out perform a 110 or 112 cam every time on a typical 455 street build. It may not idle
better but will certainly perform better!!!! And if I am serious about a street strip build it will be tighter than that.
Len C
-------

Middle of page 4 - http://speedtalk.com/forum/viewtopic.php?f=1&t=46038

[ponyakr]

"...Isky Magnum 245/245 104 LS 104/104 LSA, that I installed 4* adv for 100/108 LCs...Anyone got such a cam?."


Are these close enuff ? Or is the low LSA what you're after ?

http://iskycams.com/cart/index.php?m...oducts_id=1433

https://www.summitracing.com/parts/c...w/make/pontiac


"...It may not idle better but will certainly perform better!!!! And if I am serious about a street strip build it will be tighter than that.
Len C "

I assume this guy is lookin only at max upper end hp, and definitely NOT street manners.

I've got the CC 292 in a 455/6x-8 heads bracket engine. Even with Rhoads lifters, it sounds pretty nasty to me. I have manual brakes. Would not wanna try this cam in a street driven power brakes car. And I assume it would be even worse with a lower LSA. But, I'm very obviously no cam expert.

[Formulajones]

Originally Posted by pastry_chef

Does anyone wonder why Len Caverly would make a comment like this?

For those who do not know Len.
He has his own dyno, ports heads, owns high end analysis software and competed in Engine Masters.

------
I do Pontiacs and yes a 108 cam will out perform a 110 or 112 cam every time on a typical 455 street build. It may not idle
better but will certainly perform better!!!! And if I am serious about a street strip build it will be tighter than that.
Len C
-------

Middle of page 4 - http://speedtalk.com/forum/viewtopic.php?f=1&t=46038

There are a lot of well respected and very smart engine builders that go this direction. I don't think there is a right or wrong. Tony Bischoff spec'd a 110 LSA for a pump gas 571 he built for my father. Even Kauffman spec'd a 110 LSA for a pump gas 455 he built for him a few years back, using his heads. That's a well respected Pontiac builder doing that.
While these aren't super tight LSA's, it still contradicts what others suggest :shrug: But I do see why some want to spread that number out a bit too. Tons of variables.

[pastry_chef]

Originally Posted by ponyakr

I assume this guy is lookin only at max upper end hp, and definitely NOT street manners.

Nope, please note in the exact quote the words "EVERYTIME", "typical 455 street build"

He confirms "won't idle better"

When Len said that I knew he was the real deal.
Often the best cam designers I know spec 107 or 108 LSA for a hot street combo.

Too many whine about "the rumble" or vacuum being a little low.
Contradictory to max power even in a street RPM range.
About proper lobe area and proper open / close events.

[Formulajones]

I find the tighter LSA cams streetable, and work just fine for us. I will say they take a bit more tuning finesse to make them happy and easier to drive.

You can't just toss a distributor in, set initial at 10 degrees, slap on a carb and call it good. You need to be familiar with idle feed circuits, how they work and how they can be modified in a particular carb being used, and a little distributor magic.

The wide LSA's with minimal duration are very forgiving, easy to tune/make behave, and don't really show ill manors if the tune isn't perfect, and I think that appeals to a lot of people.

[Half-Inch Stud]

@ponyaker, lower LSA . Know of any off-the-shelf 104 LSA cams? 236/240 duration or close may get my wallet out.

[ponyakr]

Originally Posted by Half-Inch Stud

@ponyaker, lower LSA . Know of any off-the-shelf 104 LSA cams? 236/240 duration or close may get my wallet out.

No, but if you really want a super low LSA that bad, for a few more bucks you can get one ground any way you want it.

http://www.bulletcams.com/Masters/Hlobes.htm

My guess is that the reason there are no shelf grinds with an LSA that low is that there is absolutely no demand for 'em.

Here's a 230/238 with a 108 LSA.

http://schneidercams.com/288-96Hponhydraulic.aspx

Erson sells single pattern 228 & 240 cams with 108 LSA.

https://www.scribd.com/document/3314...-Erson-Catalog

Howards has a 231 with 108 LSA.

https://www.summitracing.com/parts/hrs-410961-08

Crower 236/242 108 LSA

http://www.cnc-motorsports.com/crowe...-camshaft.html

[tom s]

Comp will grind a custom cam also.Go to their lobe list and pick what you want and have them grinde it your way.I have had them grind them for me with no built in advance etc.Tom

[pastry_chef]

Easy to pick LSA right down to 104 here:

http://www.claysmithcams.com/h-9000-...ppet-camshaft/

Advertised Duration: 290 Intake / 300 Exhaust
Duration at .050 : 236Intake / 244 Exhaust

--------------------------------------

Attached image from Isky cams catalogue - Pontiac hyd flats.

The LSA is the far right column, 108 for all.

[Half-Inch Stud]

Originally Posted by Half-Inch Stud

@ponyaker......

Well you sure found a trove of off-the-shelf 108 LSA cams. Thanks

[Half-Inch Stud]

Originally Posted by pastry_chef

Easy to pick LSA right down to 104 here:

http://www.claysmithcams.com/h-9000-...ppet-camshaft/

Advertised Duration: 290 Intake / 300 Exhaust
Duration at .050 : 236Intake / 244 Exhaust...........

Wow, never heard of Claysmithcams. They may be to deliver the goods. Has anyone here used their cams and performed in the 1/4 and not lose lobes?

[pastry_chef]

Originally Posted by Half-Inch Stud

Wow, never heard of Claysmithcams. They may be to deliver the goods. Has anyone here used their cams and performed in the 1/4 and not lose lobes?

Clay Smith cams are a legend.

[pastry_chef]

Great quote on the Crower Hyd Flat - 60213 with 108 LSA

EXPLOSIVE power.. how about that.

Think about comparing drag times of a flat cam to roller cam and ported heads. Not fair at all.
-------------------------------------------

Originally Posted by Cliff R

As it relates to this topic we built a pretty "basic" 455 a few years back, and installed mildly ported heads small chamber heads on it, and 247/254/108LSA cam. That engine idled with a LOT of authority, and to this day was one of the hardest hitting 455's I've ever driven in a street car. The power curve was EXPLOSIVE, and if evaluated by the "seat of your pants" you'd have bet the car would have ran into the 10's. The big cam on a 108LSA created a huge "rush" of power in the mid-range, much like a shot of nitrous, it was very impressive.

At the track the combo didn't run pretty decent, car was/is well set up, best of 12.28 at 112mph. We tuned and tuned on it, and that's all it had.

A couple of years later we had Dave at SD cnc port the heads, and send them back with his Road Paver camshaft. It's very similar for .050" specs, but on a much wider 112LSA. There were no other changes made anyplace, just the cam and heads. On the street, the new combo idled pretty smooth, slight hint of something going on at idle, and produces a broad/smooth power curve. No rush of power anyplace, just pulls smooth and hard thru the rpm range. It's actually somewhat "boring" to drive, as there is no "rush" of power anyplace, just pulls like a big locomotive.

At the track the new combo runs 11.30's at 119mph

[ponyakr]

Originally Posted by pastry_chef

Clay Smith cams are a legend.

I'm familiar with the woodpecker logo. But I thought the cams were history.

https://en.wikipedia.org/wiki/Mr._Horsepower

http://www.speedwaymotors.com/Mr-Hor...ign,81820.html

[ponyakr]

Hey, I forgot about the Thumpr cams. They have a 107 LSA.

http://www.compcams.com/Company/CC/c...csid=1470&sb=2

http://www.compcams.com/Company/CC/c...csid=1532&sb=2

http://www.compcams.com/Company/CC/c...csid=1469&sb=2

[Formulajones]

Originally Posted by Half-Inch Stud

Wow, never heard of Claysmithcams. They may be to deliver the goods. Has anyone here used their cams and performed in the 1/4 and not lose lobes?

Been around for eons. We have a 327 out here that's had one of their solid flat tappets in it since the late 60's.

[Cliff R]

"...It may not idle better but will certainly perform better!!!! And if I am serious about a street strip build it will be tighter than that.
Len C "

I assume this guy is lookin only at max upper end hp, and definitely NOT street manners."


Maybe Len and Dave Vizard need to come on to one of these discussions and defend their comments and camshaft recommendations? Copy/pasting quotes does NOT tell us the whole story as to why someone would use and recommend super-tight LSA cams for one of these engines.

Right to start with, IF you pick a cam big enough to make big HP, it's going to be a complete TURD in a relatively low compression 455 build with really tight LSA. (The engine I was quoted on above had over 11 to 1 compression with the huge 108LSA cam, and still very rough idle and poor street manners at low rpm's, in case anyone is taking notes here.) Idle quality will be horrible, really stinky exhaust, and not user friendly anyplace. With high compression you can start pulling the LSA down with less negatives, as the added static compression trumps the increased overlap.

As far as the "Thumper" camshafts, I get so many complaints from folks who went that route I put those cams in the same category as the Comp XE grinds, stay as far away from them as possible if you are attempting to build a successful Pontiac "street" engine.

I've actually worked DIRECTLY with quite a few customers who used the Thumper cams in "fresh" BBC engine builds, and ALL of them have removed them due for various reasons, and went to cams on much wider LSA's. The biggest complaint all of them had was very difficult to tune them for decent idle quality, super-stinky exhaust, and very poor street manners in the "normal" driving range.

I'll also say that a high percentage of those folks also lowered the static compression at or below 9.5 to 1 for pump gas, following Internet jargon or recommendations from machine shops/engine builders.

One that comes to mind recently was a poor soul with a very nice late 60's Chevelle restoration with a factory 396 and 4 speed. His machinist/engine builder lowered the compression to mid 9 to 1 for pump gas, then threw in a Mutha-Thumper cam on a 107LSA, and around 235/249 @ .050". He told the customer that he had successfully used that cam in a good number of BBC engine builds.

I got involved as we did the carb/distributor here. We got them to work fine, but he had to run a LOT of initial timing, and the engine idled very rough and very stinky. Even after we nailed down the tune and the car was being used for car shows and such, the owner quickly got sick and tired of the "bling" associated with that cam, and his wife absolutely refused to ride in the car as it was just too "stinky".

He ended up installing a factory reproduction cam on a 115LSA, and although a tad "boring" at idle, he said it ran better everywhere than the Thumper cam, with good street manners and very broad/flat power curve. Doing this of course required that we did the carb and distributor again, to put "normal" timing and fuel curves in the engine for best results.

Since I do this for a living, we get to see a LOT of this sort of thing. So I don't come on here and make comments and recommendations based on what I "googled" up then copy/pasted about what someone else was doing.......which seems to be the trend on here lately when it comes to camshaft discussions and recommendations.....FWIW......Cliff

[Formulajones]

Thumpers aren't all that bad. I ran one in a 406 sbc, Dart heads, 10:1 compression, M-20 4-speed with 3.08 gears out back. Had an RPM air gap with a 750 holley on top. I daily drove it, and made several 300 mile round trips in it on occasions. It idled and ran great, didn't stink. Made great power right off idle and in that engine it pulled to about 56-5700 before it seemed to run out of steam.

Have to be clear, there are 3 versions of it, one bigger than the next. I ran the middle version called the Mutha-Thumper in my 406. Not sure if your customer complaints are coming from guys trying to run the biggest one in the catalog in a relatively small engine, but my experiences with them, with correct tuning, and chosen wisely for the application, is nothing like you're reporting here.

I will say I probably wouldn't be as happy with it if the car had an automatic with it. Having a clutch pedal makes things much easier to drive, idle, and loaf through traffic. Was always a blast to drive, and sounded great, very snappy throttle response.

[Formulajones]

Here's a short idle clip of it. Always started right up, no choke, and after minute would settle down into a nice idle. I drove this thing all over the place.


https://youtu.be/47HgejCVbFs

[Formulajones]

And before anyone says anything, no I didn't put a chevy motor in it, It's 100% factory with a 307 SBC so GM bastardized that car already in 1971

It's original numbers matching 307 engine is in the backround of this video sitting on a dolly.

Just for giggles, that original 307 with rated 8.5:1 compression and it's little 1.72 valve heads, an old isky 224 @ .050 cam with .460 lift, performer intake and a 600 double pumper pushed this car to a 14.56 ET with the M-20 and 3.08 gears on stock rubber. Always got a kick out of that, no one believed a 307 would do that, lol. Originally this is a 2 barrel engine (only V8 available in this car in 1971) and was a 3 speed manual floor shift with buckets. 60k original miles and unrestored original paint.