Technical Cam Selection Question

To me a rod or custom has to have a lope when it idles. We will be using a SBC carbureted motor, not modified except for a Dual plane intake with a 4 barrel carb, 350T/H Trans with a slight stall converter, stock heads, stock valves,lifters and rockers etc .I am no authority when it comes to cams ,duration ,overlap etc.
I don't want anything radical, don't want to lose vacuum or lose cruising comfortably.
having a hot engine- those days are over...
From what I have mentioned what should I buy? ,name brand and quality is important.

Thanks Much Gene

 

Hahahahahahahah
That's funny

 

Hey ,someday you will be old too and have slowed down. How many people do you know that are over 70 yrs old and still building hot rods??

 

In most cases you will want to improve the valve springs. I recommend you call a cam help line. I know Comp cams has that service. They will want to know compression ratio, displacement, valve size, etc. I suspect with the few mods you have done they will recommend a mild cam that might night sound like you want but will give you good all around performance.

 

Try a Comp 268. Recurve the dist for early limited advance and set your initial around 15 ish then lean out the idle. Gives a nice choppy idle

 

Just a few and my hat is off to all.

But Here's why it's funny -
That Lopey idle is an unintended consequence of an engine that's built to run hard in the upper RPM ranges. See its actually struggling to idle hence the lope.

So when you say a must have item is the "lope at idle" (or the unintended) but exclude all of the factors that actually produce the unintended consequence of a Lopey idle its really funny.


Need to Develope a word for this, the definition:
Seeking a way to produce a not planned or meant result.

What's the word ?

 

I like the sound and power a 3836151 Chev cam gives, and it's real old school, too.....

 

Aren't there some cam manufacturers that make "thumper" cams, or something like that, with all of the sound and none of the performance?

Or you could just put a manual choke on it and pull it halfway out when you want to have the nasty idle. I used to ride Moto Guzzi bikes with Dellorto carbs, and they had an "enrichening" circuit whose purpose was aid in cold starts, but when you engaged them at idle the bikes sounded like they were really cammed up. A choke halfway on will do the same thing. It'll also make black smoke, wash down your cylinder walls, dirty your oil and wear out your rings, but hey, it'll make the sound you want.

 

Call the comp cams tech line.


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ME"-78

 

Comp Camps Thumpr cams... and I wouldn't necessarily say you don't get some additional performance with the lopey sound these cams will give you, and there are better performing cams... but with the parameters you listed these get my vote...

 

as mentioned above, a comp cams 268, or an Isky 262 super cam will give you a little lope at idle, with good vacuum. Not gonna sound like a race car, but with the right sized pipes and mufflers you can accentuate the sound. Stick with 2 inch pipes, and a good set of gl***packs with the smaller cam and you will sound pretty good. Personally I am not a fan of the "Thumpre" cams concept, but I have never run one. I like the factory grinds, such as the 350 horse 327 cam, but not with a low compression motor like you have. I used the Isky 262 for years, probably my favorite cam.

 

I was surprised when my engine machine shop guy said he really likes the Thumper cams, I thought they were a gimmick. But he builds some serious motors (had a 2700 hp BBC on the dyno one day) so he knows his stuff.

So, to answer your question, look into the Thumper cams, you should get the idle and a little better performance too.

Don

 

Humm. So this weekend's pleasure has been to slide the Crower hi-lube tappets down on the Duntov 097, seated with the Comp Cam's 3/8th" magnum push rods rocking Comp Cam's Pro Magnum roller rockers.

Lope? Oh yeah, its going to be there, along with abrupt rev ability . But, its going to be coupled to a T-10 and I just don't think that enjoyable driveability would be there with a 350 auto. Comp Cams does have some Great modern cams that will do very nicely.

Have fun!

 

I ran a small Thumper cam (they have 3 levels of Thumper cams) in a 454 Chevy with 4 speed in my 65 El Camino, and it produced very good power and performance. I called Comp for a cam recommendation, and I asked specifically if their 268 degree cam might be best for my application. The tech guy told me he thought the small Thumper cam would out-perform the 268 in my case. Here's what I had: stock 454 with peanut port truck heads, Edelbrock RPM Air Gap manifold, 750 Holley, Crane roller rockers, large tube ****** headers, MSD ignition, 3" exhaust all the way with Flowmaster mufflers, Muncie 4 speed, and 3.55 rear gears. I sold the El Camino to buy a 29 Model A roadster pickup, but I have to say, it ran very well, with no bad habits other than terrible gas mileage, but that's pretty much characteristic of any big block Chevy. Incidentally, it sounded real good. As per the cam tech guy's recommendation, I used the stock valve springs with no issues, and the engine pulled strong to 5000 RPM.



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