Author Topic: power gains  (Read 9831 times)

Offline cwilson jr

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power gains
« on: November 29, 2008, 02:49:59 pm »
i have an 85 with a stock 350 replacement and doesn't have nearly enough power to do what i use it for.  it has issues towing anything up inclines while traveling through mountains on the interstate and overheats on me.  if i replaced the carb with an edelbrock 1406 or any other suggestions on brand/model about how much more of a gain would i add to the weak 160 i believe HP, i have now.  also later if i added a better intake mainfold, such as an edelbrock 2101, what i'm looking at now,  would that help at all?  like i stated before i'm open to any suggestions on bolt-ons, mods or what i could do to get a little more umph to where i can tow and not overheat.  i'm trying to avoid picking up a crate motor at the moment and don't think i should with the little towing i do, such as cabin trailers, a small car on a dolley, etc.

Offline bigkountry

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Re: power gains
« Reply #1 on: November 29, 2008, 02:53:20 pm »
More info on the truck?

Most of the time you can start with an exhaust upgrade and carb/intake combo and get better power. The overheating is another issue though.
81 Scottsdale K10 "Under construction"

Offline VileZambonie

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Re: power gains
« Reply #2 on: November 29, 2008, 03:20:35 pm »
yep, address your overheating issue before you start pumping money into it.

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Offline cwilson jr

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Re: power gains
« Reply #3 on: November 29, 2008, 03:27:41 pm »
lol.  no, i meant it only overheats when trying to tow up steep inclines.  it is an 85 K10 silverado with a stock replacement 350.

Offline jw454

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Re: power gains
« Reply #4 on: November 29, 2008, 03:35:09 pm »
The cheapest and most effective upgrades would be a good set of headers with true dual exhaust, an aluminum dual plane intake, and re-jetting or replacing your carb with something no more than 600cfm. A carb this size will keep low and mid range intake velocities high, which makes for good cylinder filling. When you go to headers, you will have to re-jet or change metering rods for a richer fuel ratio. The engine will breathe better and will require more fuel to even out the increased volume of air. As far as overheating, the equipment mentioned will help the engine to labor less and in turn run cooler. What size radiator and what temp. thermostat does the truck have?
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Offline HAULIN IT

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Re: power gains
« Reply #5 on: November 29, 2008, 06:01:13 pm »
I'll give my thoughts to your questions. If you have a correctly working Q-jet, jetted to achieve about 13:1-13.5:1 air/fuel ratio under power, then you remove it & install the Edelbrock carb, the true horsepower difference will most likely be VERY little if any, it's a fuel mixing device & if it's doing that job, that's about as good as it gets.  Now if your carb isn't working properly, then things are different, but the Edelbrock isn't the hero, you just went about fixing a problem a different way. As for the Performer intake, I'd expect about the same (maybe 5 hp).
 An engine turning 4000 rpm's or so max, that is producing about 160 hp has other, bigger problems. It's cfm demand is low, the stock intakes are poor, but not real poor for a engine like your describing.
 Now take a 350+ hp engine with a stock intake & swap to the Performer & you may see the gains you wish we were talking about (15+), as for the carb....I wish so many guys weren't so eager to give up their Q-jets, they are a very good all-around carb when set-up properly. I'm sure this isn't the answer your looking for, but I think it is realistic.
 Your best bet is to confirm the innards of the engine are sound, tune the carb you have, put a good ignition tune to it & as mentioned...work on the exhaust, it is far more of a restriction in stock from than the intake tract.
 Save your money for a good, efficient torque motor (a 383 would be the most cost effective plan)
 That's all for me. Have Fun, Lorne 
     

Offline Lt.Del

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Re: power gains
« Reply #6 on: November 30, 2008, 11:35:40 am »
Quote
(a 383 would be the most cost effective plan)

for pulling, that is exactly what you need...all the 350 parts will bolt right up. Lotza Torque.

Now, for overheating when pulling, if your radiator is not at least a 3 core, you will overheat when pulling over hills.  Did your truck come with AC? if so, the radiator should be fine, they put at least 3-cores in those.

Lower your rear axle ratio.  If you have  a 2.56 or similar high gear rear, your truck won't be good for pulling.  Put in a 3.50 rear.

As for losing power uphill, make sure your exhaust / catatytic convert, etc.. is not full of carbon and crud.   A closed exhauast system will cause truck to overheat and lose power.   
« Last Edit: November 30, 2008, 11:37:20 am by SgtDel »

Offline Stewart G Griffin

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Re: power gains
« Reply #7 on: November 30, 2008, 11:42:02 am »
You may have the wrong vehicle for the job;  i have a similar setup as yours and occasionally haul light (under 2500lb) trailers and occasional heavy loads.  i can do this all day on relatively flat land with no problems and the truck is hardly straining-----and this is with 2.56 rear gear.

However, if you are talking about the type of inclines that i am picturing in my mind-----long grades at 55mph and above, then i would probably overheat too.

i don't think the "hot rod" type add ons are the solution in this case;  If anything, a gear change might be in order.  Also, you may need a higher capacity cooling system.  Auxillary oil and trans cooler.

We need more info on the truck;  Such as, what's the final drive ratio, tire size and type, transmission etc.

i would also agree with Mr. Hauling in that getting the engine in top tune would be the first order of business and that for towing you need torque not HP.

Offline Stewart G Griffin

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Re: power gains
« Reply #8 on: November 30, 2008, 11:46:59 am »
P.S., i can see the Sgt. posted a few mins before me as i was typing up my answer and pretty much stated exactly everything i was going to say-----so i pretty much wasted my energy.   But good luck and let us know your strategy.

Offline jw454

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Re: power gains
« Reply #9 on: November 30, 2008, 12:06:24 pm »
There is no such thing as "top tune" with stock exhaust manifolds and a two into one exhaust pipe. The best you can hope for is "barely satisfactory". Any engine will benefit from a free flowing exhaust, and since exhaust is only half the picture in the total breathing potential of the engine, then the intake must be addressed as well, whether it be a stock or modified engine.
Nothing says power like cubic inches!

Offline eventhorizon66

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Re: power gains
« Reply #10 on: November 30, 2008, 01:34:44 pm »
I agree with what others have said here.  Definitely go with a set of headers and a free-flowing exhaust.  Look for headers with 3/8" thick flanges, 1.5" or 1.625" diameter primaries, and 14 or 16 ga wall tubing.  Unless you plan on bigger cam, more compression, etc., don't even bother with a 2101 intake.  It can't even come close to the low-end torque of a stock q-jet manifold, and really only starts to show gains above 3000 rpm.  And unless the plans are to get serious about high-performance, keep the Q-jet; they're the best carb for a stock engine.  Oh, and another suggestion would be to consider a hotter spark with an aftermarket coil, module, cap, and rotor like this kit.  And, of course, buy an advance timing light and play with your timing until you achieve the best power/economy without pinging.  The kit above will allow you to adjust the amount of vacuum advance as well as the rate of mechanical advance.  There, now you have my two cents as well.

But like Vile said, I'd fix your cooling issue first, even if it only overheats while towing up inclines.  More horsepower means still more heat, so it might make your cooling issues worse to make any power modifications (although, exhaust mods can reduce engine heat, by relieving backpressure).
« Last Edit: November 30, 2008, 01:49:48 pm by eventhorizon66 »
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Offline choptop

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Re: power gains
« Reply #11 on: November 30, 2008, 02:32:36 pm »
just a thought. have you had your catalytic convertor tested. A friend had an 84 that started getting hot pulling his race car, and never had previuos problems. Replace the radiator, not help, and it lost power as well, more noticably when warmed up. Found the cat had clogged up. Replace it, and she was back to life. Check there. I know 160 hp is lame, but my 81 3/4 ton only had 165 and pulled a backhoe around without any issues.
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Offline jw454

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Re: power gains
« Reply #12 on: November 30, 2008, 02:58:54 pm »
A 2101 intake is for stock to mildly modified engines and is suitable for off idle to 5500 rpm. It is capable of creating at least as much off idle torque as a stock GM intake, weighs less and dissipates heat faster. If you were in the market for an intake, the 2101 or similar would be the one to use. Get your headers and dual exhaust, and you can forget about the catalytic converter.
Nothing says power like cubic inches!