My New 350 HO

I got a new 350 HO about a month ago. GM dynod it at 330 hp  and 380 ft. lbs. torque on just the engine, with headers. I however have exhaust manifold, and it just isn't quite as powerful as i would like. would putting on headers and be a good first step. I use this car to drive around, but not a daily driver.
   im getting like 11 second 0-60, which isn't great
advice, help?
1975 nova
350 HO new crate
TH350 auto trans
limited slip
street tires
600 Holley carb
Hei dist
        e-mail:rdbosse@yahoo.com  

Yes a good set of headers will help but the gm crate engines do not have the power gm says they have reguardless what they tell you.  
Professional hi-performance engine builder

Horsepower sells Engines and torque wins races.

Pontiacman:
Yes a good set of headers will help but the gm crate engines do not have the power gm says they have reguardless what they tell you.

What they tell you is advertising...and if not true, they are subject to lawsuits.  

My weak ass 305 TPI powered 88 IROC managed around 7 seconds 0-60...something is seriously wrong with the car if he's only getting 11 seconds to 60.  
68 Olds Cutlass ~ 350 Rocket
85 Delta 88 ~ 425 Rocket
02 Silverado 4X4 ~ 5.3L

yeah i know thats what i was thinking... i am just wandering what though...

is it gearing, or something  

how much hp and ft. lb. torque is in your IROC??? anyway  

rdbosse:
how much hp and ft. lb. torque is in your IROC??? anyway

Not mine anymore...

But the ratings on it were right around 200 HP (net)...I had done a few mods (increased compression, 3 angle valve job, port matched the intake, complete header to muffler exhaust system including high-flow cat, and a few other minor tricks)...but honestly don't think they did much...never felt a difference.

Previous owner may have done some stuff as well...it'd easily bark the tires from 1-2 (automatic) which suggests to me that at least a shift kit was installed...who knows what else he may have done.



Not sure on your issue though.  I'd say it could be gearing, but the presence of a limited slip kinda suggests you'd have at least a 3.08 (or so)...its possible you're stuck with something quite a bit higher.  Other issues could be a bad torque converter...bad valve springs can wreak havoc on an engine (not likely given the crate status of your motor)...carburetor secondaries not opening could cause issues...

Or the motor is just laying down on you...I really don't know  
68 Olds Cutlass ~ 350 Rocket
85 Delta 88 ~ 425 Rocket
02 Silverado 4X4 ~ 5.3L

Yeah, my 5,000lb Buick has around 330Hp (and god knows how much torque though) and it does 0-60 in the 8 second range with 2.93 gears.  
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The Silver Buick- '77 Skylark coupe w/ a Fuel Injected Buick 455&TKO-600, '72 Centurion Conv't - 455w/TH400, '67 T-bird 4Dr (suicide) w/428&C6. Needing to replace a '69 Firebird 400.

http://www.bangshift.com/forum/index.php?topic=6189.0

Well, I'd dyno the engine on a chassis dyno. Other possibilities could include the following:
1. Axle Ratio. They varied from a horrible 2.14-to a not much better 3.08.
2. Tire and rim size. If you aren't on stock tires, your speedo will not read popular. If your total diameter of tire and rim included are LARGER than the stock tire rim diameter, your speedo will read SLOWER than your actual speed.
3.Faulty engine tuning. Dyno tests almost always yield more torque and HP figures, from a variety of things. First is the alternator, fan, etc. are not attached. This reduces engine load, allowing more torque, which increase HP figures. It can stem from your tuning, versus GM's tuning when they shipped the engine to you.
4. Check for transmission or engine problems. A leaking intake manifold gasket will cause a vacuum leak, disrupting the engines vacuum signal, and it is an avalanche effect to the carb. Transmission problems can stem from faulty vacuum modulator valve. YOu may have a misdjusted detent cable, which both will cause late shifts(after the useful powerband range), or early shifts(not winding the gear out far enough, and thereby dropping the engine out of the useful powerband range). Faulty engine vacuum can disrupt shift points, and shift quality as well, through a normally functioning modulator valve.
4. Check air/fuel ratio, richer is not always better, nor is leaner. Check ignition timing. ON a 350, proper tuning can net as much as 50 more HP, without adding bolt ons.

I got a 1980 malibu with the gimpiest, sorry excuse for a v-8 I have ever seen, the 267, and it can get my 3100 lbs slug to 60 MPH in 9.84 secs. I have added bolt-ons to do that. MY car has around 160 HP, so your situation doesn't sound right at all. I'd almost run the casting number to make sure they didn't swap you an old 307 core engine that got sent in to them for rebuild. If yu need some advice, these guys here know alot of things, and you'll get lots of responses, but the most important thing to remember: Everything you do to your engine must work with the other modifcation in balance. A racing single-plane manifold will not operate very well with a street-lagal low duration Edelbrock performer plus camshaft, and stock log-style exhaust manifolds. The latter is also true. A racing cam, will not give many gains with all stock maifolds and tuning. If you decide to build it up for more power, research your build. A 350 has 1000's of possiblities for builds. How fast do you want to go, and do you have the money to do it?
Good luck.  
Guzzling gas and hauling ass, the true American way.

holy *** thanks for this answer.. basically you answered my whole question.
it's nice to know people actually answer questions instead of saying " i don't know".  

rdbosse:
holy *** thanks for this answer.. basically you answered my whole question.
it's nice to know people actually answer questions instead of saying " i don't know".

With only giving us "its slow"...its kinda hard for us to give detailed advice.  Basically FieroGT just told you to make sure your engine is in tune and to check the gear ratios and overall condition of the powertrain...

Had you told us how it idles, how the throttle response is (does it bog when you hit the gas?), if the engine is not revving well, if it lays down at a certain RPM...etc, etc, etc...we'd be able to give you specifics.

As such, we can only tell you to make sure its in tune, in good running condition, and that you aren't running insanely tall gears.  
68 Olds Cutlass ~ 350 Rocket
85 Delta 88 ~ 425 Rocket
02 Silverado 4X4 ~ 5.3L

i know i didn't give you alot of info... but do you think these symptoms could be the result of a carb. not opening up 2 out of the 4 barrels when i punch it down  

How old is the carb?  Has it been rebuilt?  Check the linkage, make sure the secondaries open easily (if it has a choke, it may have a piece that "unlocks" the secondaries when the choke fully opens).  Its not likely if the carb is relatively new, but is possible.

Check your rear axle ratio...put it up on jackstands in neutral, and turn the wheels counting the number of times the driveshaft turns for a full turn of the wheel.  Basically, if you're dealing with a really high rear end gear...it'll be like taking off in second gear in many other cars.

How does the car idle?  Smooth?  Rough?  Does the engine bog when you floor it?  A rough idle could mean a vacuum leak (possibly at the intake as FieroGT said).  If the engine bogs when you floor it, its likely a carburetor tuning issue.

As FieroGT said, if you can get to one, and can afford one...a chassis dyno would be great.

But it really is hard to supply many suggestions without a bit more information.  If you can, spend some time with the car and try to feel exactly what its doing.  There are a lot of knowledgeable people on this forum (many with more experience than I)...but they'll need more information to really help you.  We'll be glad to do so though!  
68 Olds Cutlass ~ 350 Rocket
85 Delta 88 ~ 425 Rocket
02 Silverado 4X4 ~ 5.3L

I took a look at the carb. When the pedal it pushed down, it looks like the front two barrels open up, but the back two do not. This is a brand new 600 vaccum secondary Holley.  

YOu may have a piece of linkage disconeccted then. If it has vacuum secondaries, there will be a butterfly above the actual throttle plate. These carbs are designed to "size" themselves to your engine, and are more forgiving than a mechanical secondary. You may not be able to see your throttle opening with a vacuum secondary set-up. The size of your carb is very well suited for your engine. Keep up the good work, an we'll keep up the possible trouble shooting.  
Guzzling gas and hauling ass, the true American way.

A vacuum secondary carb will not open the secondaries with the linkage...engine vacuum pulls them open.  Check it again, push the pedal down, and try to push the secondaries open...

I'd bet they will open since its brand new...meaning thats not the issue.  
68 Olds Cutlass ~ 350 Rocket
85 Delta 88 ~ 425 Rocket
02 Silverado 4X4 ~ 5.3L