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More power for my 350. ideas?

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76blazerguy

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wichita, Kansas
I currently have a 350 with a holley 4barrel 450cfm. I have a flowmaster muffler with the stock pipes. I also have a K&N filter. New wires, plugs, rotor and cap. I dont want crazy power, just it little more hp so it doesnt feel like im using all its got! Im interested in an intake but im not sure what kind would work with my carb. Sorry that might be a stupid question, im pretty new to chevy's. any one have some suggestions that arent gonna cost me big bucks.
 
well the problem im slightly concerned with headers is i have the valve that puts warm air into my air filter(sorry i cant remember what its called) and its pretty cold round here at the moment so i do like that feature. I would love to do that when it warms up but do anyone make headers that you can use the heat function with?
 
Bigger carb would help a lot. 350s should have at least 550 cfm to make power. You are chokeing it with a 450 cfm. If you want to keep that small carb there aint really much you can do to make power.
If you want to bolt on some power.A new quadrajet would be a real good start.
 
Thorley makes headers with a heat riser.. and as Thunder said, the carb is small.. my buddy just got done with a hotrod 6 cyl in a 67 van and he runs that carb..:wink1:
 
thanks guys, you are a lot of help. it came with the 450 on it and i have just took it all apart and cleaned it all etc and its already running better but that probably explains why its not to hot yet! what kind of carb do you recomend? i looked at a 650 off road thunder avs or something like that. are they any good? im going to be wheelin it when i get my lift on it. thanks for the advice on headers. has anyone used those headers before?
 
sorry to hijack, but ive got a few questions about the heat riser. is there really an advantage to using it? seems like warm air going in would cause a little power loss. it doesnt affect emisions at all does it? it doesnt seem like it would. i really dont see how its so important(i failed inspection cus i didnt have it on, cheap quick fix though). i think the only thing that i could see it helping is warming the motor up quicker and helping to unfreeze the carb or tb in those areas where its freezing alot.
 
i've never kept stock exhaust on anything i've ever owned,all chevies. and headers have never changed much as far as the little heater tube afecting the way it ran.i even had a 78 monte carlo that i took the butterfly off and ran strait 60 weight racing oil. it was a little slow but she always started,even on -16 degree days. so i don't think you need that tube .:D
 
a Quadrajet is best all around.. good rebuilds available around for $200 to $300... google search should bring up a bunch..

Thorleys are a good header. not overly cheap tho..
 
see i like the heat riser because it does help warm up a lot quicker and it does help when i have to get up early in the morning after it being outside all night! it just speeds things up really. the valve closes once it warms up. so it doesnt remain open all the time
 
How much are you looking to spend? You can gain 60 hp easy with an offroad cam, offroad carb, and a good crosswind manifold. Most likely it will be more than that but that is really all the power you'll ever need.

In 4 lo anything becomes a goat but there is a huge difference between how a four cylinder and a v8 will spin the tires. Tired of people saying a 4 banger will spin 44's....yeah it will but real slow and only in 4 lo.

The only place you need anymore hp than the 350 has stock is going up hills on the highway. My last motor was almost stock had a k&n and 3" exhaust and maybe a chip and it would shift down to third on the highway when i hit a hill. Always hated that cause i had a job at the lake and was spending 5 bucks everyday just going to work. 60 hp or a little more will cure the feeling that your using everything its got but there's ALOT of other mods you can do to a 350 to make well over 500 hp without forced induction.. but you start to feel it in your wallet.:blush:

A good offroad carb is real important because roads carbs will stall a lot sooner going up a hill than an offroad carb. If you use ebay you can get a new crosswind manifold for about 140. the crosswind design made 14 more hp than a regular edelbrock eps performer. I would get a good cam, an offroad carb about 650-750cfm, and a crosswind manifold for about $450 total on ebay. You can keep going with dyno tuning, spacers, heads, headers, intake coolers, ignition/distritbutor, fuel pump, higher rev limiter, etc etc etc its all just making a pump breath better.
 
yea, im not asking for 500-600 hp just something that will make highway driving a little less challenging for the motor and of course going up the odd steep climb would be nice. just so i can make a few comparisons what kind of off road carb do you suggest?
 
My opinion and I'm sure there's someone out there who will diasagree with me... is the heat riser really doesn't do anything to warm the engine up faster. Its just another B.S. part the factory put on the engine because the US govenment told them to. The idea behind it is to lower emissions, by warming the engine up faster because an engine makes most of its pollution before it reaches normal operating temperature. How much faster did they think it was going to warm up? I wonder if they even tested these devices before they decided all vehicles needed it. All this ingenuity was done with my tax money. Unless you live in a state where they they look for that stuff during inspection, I suggest tossing it.
Useless part #2 is that exhaust heat valve, on the passenger side exhaust manifold. Its based on the same idea as the heat riser. It stays almost closed until the engine is warmed up, then it opens - a little. Some were vacuum accuated some were mechanical. While putting headers on my buddies 88 Jimmy, we noticed the thing was siezed in the closed position! Those headers made a huge improvement.
Useless part #3 egr valve
Useless part #4 air pump
 
bigger carb!! and drop the stock manifolds go headers that tube does nothing but get in the way the temp here tomarrow will be a high of -5 and I have never left them on a single vehichle I have owned and I did emissions testing for two years and it does nothing to lower emissions


.02 :)
 
Sorry, I didn't specify, the "exhauast heat valve" is IN the bottom of the pass side minifold, in the path of the exhaust. It makes the exhaust gases swirl around inside the ex manifold. After warming up it opens and actually lets the gasses go down the pipe.
 
In the last year I have rebuilt my 350 to around 300hp, and I have swapped axles for lower gears 3.08 to 3.73.

The one that gave me the biggest seat of the pants difference was the gears.

If I had it to do over again I would have skipped the motor rebuild and just done the gears.

As far as Qjets, check out SMI Carburetor if you're not the DIY type when it comes to carbs. If I get a new Qjet, it will be from them. They will build the carb to match your vehicle and it's about $20 less than one from Jet Performance. If you go to their website there's a form you can fill out that has all your vehicle info: gears, tire size, altitude, cam, motor, etc...

Acutally the SMI stands for Sean Murphy Induction(?). Anyways, from what I understand Sean Murphy used to be Jet's Qjet guy.
 
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