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Old 09-04-2008, 08:29 AM
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wanting to build a 350hp 350.

I want to build a 350hp 350.I was thinking of using vortech heads,.030 bore,flat tops ,a 292 488 cam,air gap intake,headers,port and polished.This may not be a good combo to reach my goal.It was just rolling around my head.any suggestions?

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Old 09-04-2008, 09:19 AM
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Easily 350 hp probably 400
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Old 09-04-2008, 11:04 AM
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Getting an honest 350hp (and more) out of a 350ci SBC with vortec heads (a very good choice) is pretty easy. But, selecting the (right) camshaft for the vehicle and intended use is where a lot of people go wrong.
What vehicle will it be going into? rear gear ratio? trans type? converter stall speed (auto)?
Gas mileage? towing? hot rod? desired idle (rough, smooth)?
compression ratio? pump gas?, race gas? Stock OEM vortec heads? modified /upgraded valve train vortecs? headers? exhaust details?
*** emissions test required***? no emissions test nessessary?
Can help you with the camshaft choice (easy, bolt in cams that work great) but need some details on your project. Getting the cam just right makes all the difference in the world.

Last edited by F-BIRD'88; 09-04-2008 at 11:31 AM.
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Old 09-04-2008, 04:59 PM
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Can't remember which mag did it but they built a 355 ~9:1, stock vortecs, and a comp xe 262 that made 422hp and 450 torque. Mind you that was with 1 3/4 dyno headers and probably no accessories. But i see know reason you couldn't get ~400 REAL hp and more torque with that setup.
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Old 09-05-2008, 03:28 AM
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"a 292 488 cam"
You'd need a static compression ratio between 10.5:1 and 12.0:1 to operate the motor on this cam. That would make it a race motor, not a street motor.

"port and polished."
You might get away with wowing the geeks down at the drive-in with this, but don't say it on here. It just makes you sound stupid.

I will say one thing in your favor. At least you asked for a reasonable hp figure, not 500 like most of the dunderheads who come on here asking for combinations.

Last edited by techinspector1; 09-05-2008 at 03:37 AM.
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Old 09-05-2008, 08:38 AM
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re:350hp350

Surely port and polishing wouldn't help air flow just a little. to be stupid .My project is a 77 nova.373 posi (my drop to 411).It has a 350 turbo .shift kit small stall .but I found a 6spd that will hard to pass up.I am going to use forged flat tops ,GMPP H beam rods (good for 500hp),have the heads worked to run a bigger cam if needed.Roller rockers. I like cams with a rough idle.but i want good low and mid range torque .But not to massive that have no vac .Air gap intake with a 600 or 650 carb.Headers definently not sure how big of primarys they make for my car .I don't want any clearance issues .These are all ideas I will change what i need to reach my hp goal.(350hp and 400 torque would be cool)Weekend hotrod gas mileage is not an issue.Thanks for replies keep the ideas coming.Were do y'all have the engine combos listed on here.Might find a more interesting one.
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Old 09-05-2008, 10:29 AM
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How much of this stuff do you presently own now? carb, torque converter. rear gear ratio?
A cam with a "ruff idle" requires more than a "small stall"
Are you willing to run a 10" 3500 stall converter and 4.10's?
You can easily reach your horsepower goals amd more without "porting and polishing" the vortec heads.
But they will need modification (machining) to accomodate more than .470" valve lift.

If you want 350hp and only want to run 3.73's and a near stock stall converter, use this isky 262/270hyd cam it does not have a real "rough idle" makes very good hp (350+) and torque with easy street manors.

If you want something more racey, combine this isky 280mega cam with a 10" 3500 stall and 4.10's
It has a rough but streetable idle and makes big power. requires a modified ignition advance curve.

if you want to save some money on machining for high valve lift, substitue this cool .450" lift Isky oval track "lift rule" cam isky #201278 . This cam has a rough idle and requires a very agressive ignition timing curve but drives nice on the street.
Violent torque and power. Needs the 3500 stall and 4.10 and a 750carb.
With only .450" valve lift, all that is required is a simple drop on valve spring change (isky spring #205-D) minus inner damper) on a stock OEM vortec head.
This one does not disappoint, if you want the "street machine" idle and power.
Responsive is an under statement.
All these cams work well with 1-5/8" long tube headers and 2.5" dual exhaust and love open headers for power. A 750cfm carb is your best bet.

Last edited by F-BIRD'88; 09-05-2008 at 10:37 AM.
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Old 09-05-2008, 02:35 PM
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"Were do y'all have the engine combos listed on here."

http://www.ryanscarpage.50megs.com/combos1.html

"I like cams with a rough idle.but i want good low and mid range torque .But not to massive that have no vac."

This is called wanting your cake and eating it too. In the real world, this is not possible. A rough idle is produced by using a late intake closing event on the cam lobe so that the intake valve is still open as the piston is coming up the bore on the compression stroke. The piston pushes the air/fuel mixture backwards up the intake tract and disrupts the signal that the carburetor uses to meter fuel at the venturi and the motor becomes inefficient, producing a rough idle and low manifold vacuum. As the rpm's increase, the situation improves due to increased mixture velocity and improved cylinder packing. So, you can run a rump-rump cam on the street by using a looser converter to get past the inefficient mode of the cam at lower engine speeds and get the motor "up on the cam" sooner, but you will make low manifold vacuum at lower rpm's.
You can have rump-rump and low manifold vacuum at lower engine speeds with a cam that closes the intake valve later or you can use a shorter cam with an earlier intake valve closing point and have good manifold vacuum at lower engine speeds with no rump-rump, but you can't have it both ways.

Again, you can impress the geeks down at the drive-in with a rump-rump cam, but the older and wiser members of the crowd will identify you as a poser. I can understand the need of some fellows to use a rump-rump cam because the car is used as maybe a dual-purpose street/strip car with stiff gears and the need to make power at elevated revs, which calls for increased duration and a later intake closing point, but those who install a long cam just to try to impress others makes me want to puke on my shoes.

Last edited by techinspector1; 09-05-2008 at 03:17 PM.
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Old 09-06-2008, 01:47 PM
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re:350hp350

My stall converter is a 2500.The car came with it so,I'm wanting to make it run better.The carb is a quadrojuck ,headers are cheap and rusty,I was undecided about the gear's .As far as that feller getting sick in his shoes cause he doesn't like to hear an over sized cam thumping through the mufflers,thats almost un American. That sound has been putting smiles on mens faces for years.I'm not looking for a large cam but i would like it to sound more than a slite miss.IT'S ALL ABOUT THE HP.You guy's are very knowledgeable a friend at work told me about your site.This car is just a street car ,might race a camaro or mustang while cruising.
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Old 09-06-2008, 01:59 PM
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Quote:
Originally Posted by rockhardnova
Surely port and polishing wouldn't help air flow just a little. to be stupid

I like cams with a rough idle.but i want good low and mid range torque .But not to massive that have no vac .
.
BS. I'm trying to figure out rumprump for my fuelie cars....

Look seriously at the new CompCams Thumpr...... the small one, not the MT, or BMT. That is exactly what they are designed for. Cruising with an idle lope and excellent mid range and throttle response.
Vacuum might be borderline, depending on what you need. You can always install a reservoir can.
You want some kind of vacuum secondary or Edel type carb. No double pumpers.
Mid range torque means 1 5/8 primary headers, 24 inch collector length on long tube headers.

Factory vortec heads are the best of any factory iron head,
EngineQuest Vortec iron 180 cc heads are even better, but not worth buying if you already have factory heads.
Decent head cleanup is beneficial. Polishing is controversial.

Last edited by ScoTFrenzel; 09-06-2008 at 02:09 PM.
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Old 09-06-2008, 02:57 PM
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"As far as that feller getting sick in his shoes cause he doesn't like to hear an over sized cam thumping through the mufflers,thats almost un American."

I didn't say I don't like to hear a motor thumping, I said it makes me ill for someone to put a thumper cam in the motor just to be a poser and have the geeks think there is a race motor in the car. It's the attitude of the poser doing it, then having to prop the motor up with a higher stall converter and vacuum reservoirs and other shenanigans to make it work on the street. It's not the motor that bothers me.

I've been around drag strips since 1958 and have seen and heard thousands of genuine high-compression race motors thumping and it's music to my ears. But for someone to install a thumper cam in their street motor just to try to impress someone and make them think there's a race motor in the car turns me off. I DON'T LIKE POSERS.
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