alright so i have a stock small block 350 in my camaro now, but
i want to buy the comp cam thumper, i was thinking about roller rocking it but idk if i would gain anything from it, or if i should just use the old style set up? what one is better, this is the cam i want if i was going to roller rock it - http://www.summitracing.com/parts/CCA-12-601-8/
and this one if i wasnt - http://www.summitracing.com/parts/CCA-12-600-4/

okay so on to my other question or help would be, i need valve springs, push rods, timing chain, rock arms, etc
and i have no idea on what ones to get to go with those cams, i know they make kits but i dont wanna spend all that money at once since im not gonna be doing this till spring.
if anyone is running that cam in a stock engine like mine can i get some help in what i need to buy?
pleasse and thanks guys !

 

How "stock" is that 350? If you mean it's stock except for an intake and headers, forget about that giant cam. WAY too much in a near-stock 350 (most of which have only 8.5:1 compression and lousy heads).

The most common "stock" 350 cam, like was used in most pickup truck engines as well as passenger car 350s back in the 1970s specs in about 192*/201* duration @ .050 on a 112* LSA with lift around .400". The cam you're looking at is FORTY DEGREES MORE DURATION. That is a GIGANTIC change. It will be a pig.

If you want a nice upgrade, look at something with about 210-215* duration @ .050 on a ~110* LSA. Keep the lift under .470" and you won't need any machine work to the heads to handle the lift. Springs for a setup like that would be typical Comp 981s or cheap eBay "Z28" springs which are drop-in replacements for the stockers. You can reuse your stock rockers and pushrods, too.

May not sound like much of a change, but from about 2500-3000 on up it will pull a lot better- the kind of change you don't need a dyno to tell you it's making more power. And you can still run cheap gas.

 

That cam is for roller LIFTERS; completely different to roller ROCKERS
Can put roller ROCKERS on any engine

To use a roller cam such as 12-601-8 in place of a flat tappet cam like the 12-600-4;
need roller lifters , new pushrods and other parts depending what block you have

 

yea i know the difference between them...
i was asking what one would be better, is there an advantage to a roller one

but damon im looking for that nice aggressive sound, so i do want a cam that will make that sound.. if i have to get work done to the heads ill have it done, i was just asking what cam should i go with and what parts ( pushrods, lifts, etc) would go good with it. There is a shop near me that builds engines and what not and i was already gonna take my heads there to have them re worked, so should i just ask them what i would need to run one of those cams?

or if there is a different cam out there that will make my car have that sound but with less work required i would like to know.

but thanks for all the info it was helpful!

 

http://www.summitracing.com/parts/LUN-06106/
http://www.summitracing.com/parts/CCA-09-415-8/
what about these cams ? it basically has everything you where talking about damon

 

Any reciprocating internal combustion engine has this problem, but v8s are what we are discussing. An engine has a window where it is most efficient, and by window, I mean RPM range. A 70s smogger 350 is efficient from about... 1000 RPMs to 3500 RPMs. A TPI L98 350 is efficient from about... 1000 RPMs to 4500. The average street strip car that makes that sound that you like is efficient from about.... 3000 RPMs to 7000 RPMs.

Those guys have their entire cars built around being able to run a cam that large. You have to optimize the entire car to handle a working power band so high in the RPM range. That means shorter ratio axle gears, that means a posi, that means a built tansmission and a stall coverter, higher compression ratios, a good exhaust, headers, special workarounds to get power brakes with low vacuum, carburetors or highly tuned EFI systems, single-plane carburetor intakes and some serious cylinder heads, etc.

That sound you like is the sound of an engine that's running like garbage at idle. It's misfiring and failing to ignite cylinders and barely running. These engines are built to work well atl ow RPMs, they are built to make power at the high RPMs. You see those cams run like crap at low RPMs because they have so much overlap they bleed off intake charge and they bleed off compression. At high RPMs the engine is turning so fast that the intake air doesnt have time to go straight back out of the exhaust valve that's still open. In order to run a cam that bleeds off so much compression, you have to run a higher compression ratio just so the engine will run well at all.

Why do you go through all this trouble and sacrifice to shift the focus from low RPM to high RPM? Well it's because horsepower wins races. And horsepower is torque multiplied by RPMs and then multiplied by a constant conversion factor. The reason you cant make horsepower with TPI is because it's tuned for low RPMs. You can make enough torque to move an oil tanker at 3000 RPMs, but 450 ft lbs at 3000 RPMs is basically half as much horsepower as 450 ft lbs at 6000 RPMs. Make sense?

So we go through all these hurdles to make sure we can make power at high RPMs, and we do it at the detriment of low RPM drivability.

This is why you go to the track and see a bunch of cars on trailers - some of them arent really daily drivers. They're just not that fun on the street - they're not built for that.

So what does that mean for the rest of us who want to have street cars AND want to make horsepower?

We have to make drivability sacrifices, and we have to be modest on cam selection. The better your heads, the higher your compresson ratio, the better your exhaust, the better your torque converter, and the better your gears, the bigger cam you can get away with. Its important to have the WHOLE CAR optimized for a big cam.



So to answer your question, what do you need to do to run a cam that sounds nasty and mean...

You need:

New pistons
new heads
10.0:1+ compression
aftermarket stall converter
shorter rear end gears installed (3.73s at least)
AT LEAST a 3 inch single exhaust with shorties
a single plane carburetor intake
a big carburetor, 750 cfm+


The problem is if you get a cam that pulls to 7000 RPMs or so, you will need to buy a stronger bottom end to handle that too, so add another $1500 worth of crankshaft, rods, and pistons.

So you cant just throw an intake on and be able to run a large cam. You need to raise the compression ratio, which basically necessitates a full rebuild of that engine.

BUT if you do all of that, it not only will it sound good, but you'll have a 12 second car.

Those thumpr cams are good at getting that sound without all the high end power you get from a normal cam. They still dont kick in til about 3000 RPMs. You will have to accept the fact that at highway speeds you are going to be at 3000-4000 RPMs.

Do you have a roller block or a flat tappet block? This is very important.

 

a tappet block.
Im assuming it is since the engine code for it says its a 1978 350 2 bolt main

 

If its a 78 block it's definitely a flat tappet block. Do you want to spend an extra $1k to run a roller cam? You will get better performance, better streetability, and better reliability out of a roller cam setup, but it costs money.

You will need retrofit roller tappet lifters and I think pretty much any Gen I sbc (and Gen II if you grind down the dowel pin) will work with retrofit roller lifters. You then need to get some strong valve springs to handle the more aggressive roller cams (this is why roller cam tech is superior - they can be FAR more aggressive than any flat tappe cam ever was, getting you more power at the same streetability level, but it requires beefier parts) and you'll probably want screw-in studs and some decent rocker arms too. You'll also need to set up the timing cover correctly to handle roller camshafts' tendency to walk forward and back in the block.

Also, due to the fact that roller cams are so much more efficient at getting power and maintaining vacuum at the same time, you will have to go fairly big on them to get that sound. Which will make for a VERY fast car, but you need to have all the supporting hardware to run it. That means gears, torque converter, compression, good cylinder heads, intake, carb, etc.

 

alright
well this spring im taking the engine and tranny out, tranny needs to be re built, i know a guy who owns a shop and will make my 700r4 almost bullet proof.
as far as the engine i wanna start buying what i need little by little till then, and yea all that info helps but id rather have like a list infront of me of like name brands or options i can choose from ya know?
if i want that should i just go to the speed shop around here and ask them what i need ? or can one of you take the time to help me out
either way this is all good info , i had no idea at first just adding a cam needed all this lol

 

Plan to discard everything from your current engine but the block and the oil pan. Reusing the crank wouldnt be a bad idea, though. Rods, pistons, bearings, heads, gaskets, intake, carb, cam, valvetrain, etc. Are you ready for a huge rebuild that will cost you $2000-$4000?

And then you'll need a looser torque converter to allow a large-cammed engine to get into the power band during racing and street driving. And then you'll need some 3.42-4.10 gears for the same reason.

 

Yeah, you're getting pretty good advice here. As long as you realize that A LOT of other stuff will have to be upgraded in that engine to effectively support a "lumpy" cam, such as you desire.

If you just want to upgrade the cam and do a few bolt-ons, stick with a mild cam such as I described. It'll go faster even though you won't get a raucous idle.

Remember a good running engine is the result of a SYSTEM of compatible parts. The "holy trinity" in that equation is heads, cam and compression. Those three must be matched if you want it to perform acceptably. Right now you have low compression, mediocre heads and a small cam. Not great for sucking the headlights out of a LS1 Vette, but reasonably well matched (and cheap as all get-out). If you want a big cam you need the compression and heads to be able to support the significantly higher RPM range that cam is going to want to work in.

On the street, happiness is often a cam that's 2 or 3 notches smaller than you think you need.

 

alright,
well ive been debting if i wanna do that to my 350 ,or if i wanna buy the lm7 engine and carb that.
ive heard that you can put the ls3 cam in one of those with the ls3 valve springs but im not sure, but would that give me more power with less work going that way tho?
cause i love the way those engines look in a 3rd then. and where i work i can get a good running lm7 for a steal.
jw what you think about that idea as well

 

That still wont get you that sound you want.

 

well yea i know, but since its apparent im gonna have to spend alot of money to get that sound, id rather go for hp now, and wouldnt putting one of those in make more hp with less work then my 350 i have now?

 

if your looking for a great sounding cam without loosing any bottom end and useing stock springs,crane 274ho6,450 lift/218@50 106 lsa.elgin also copies this gring pt.#1785 85 bucks from competion products,,i have used this cam in both 350 and 305s..

 

One year for a final year student project we got a group to build a car exhaust simulator. We recorded the sounds of various cars that we liked and then using an output from the distributor changed the frequency of the sound with a DSP (Digital Signal Processor). This was amplified through an amp and a big-*** speaker. Perhaps this would suit you better?

 

...yea im looking for serious help here not a smart *** remark there..

thanks 86 gasser ill deff look into that

 

Sorry, just a bit of humour, you seem more interested in the sound than anything else.