Stock Chevy 350 power upgrades

[Burbinator]

I know it’s been talked about for years, but I figured I could be very specific. I have a 1986 GMC Suburban K1500 with an emissions 350 sbc. I know Vortec is a good way to go, but what can I do to it without going to heads. Cam? Intake? Etc. Vortec stuff will put me over $1k. What can I do to improve horsepower for less? And I do plan on removing all the emission accessories and garbage to clean it up.

Also im running a Edelbrock 1406. I don’t want to go back to a Quadrajet.

Ask any other questions and I’ll answer.

Pic of rig for reference

 

[1lejohn]

A camshaft, headers, gears, intake manifold all would give some performance. The Eddy 1406 will have to be tuned if you make changes. In all reality a good tune up would probably surprise you with a performance gain. Timing, plugs wires, dizzy cap. If the emission systems are in good working order they should be left in place. The cylinder heads and compression ratio are your largest limiting factors.

 

[Sad Sack]

Throw a boatload of mothballs in the gas tank and enjoy.


But seriously. throw some Vette 2.5" rams horn manifolds on (if they'll clear). Dual plane manifold and maybe a 268H cam.

 

[Hilllbilly]

. deleted.. wrong thread

 

[Ricko1966]

What intake do you have on it now? What gears do you have?

 

[Burbinator]

What intake do you have on it now? What gears do you have?

Stock gears and everything. I did a factory tuneup (plugs, wires, dizzy). Intake is stock

 

[Ricko1966]

Stock gears and everything. I did a factory tuneup (plugs, wires, dizzy). Intake is stock

So look in the glove box and find out what gears it has.

 

[Burbinator]

So look in the glove box and find out what gears it has.

That’s the one issue… the glove box was stolen before I bought the truck (no joke) and I got a new one. So I have no idea what gears I have

 

[Burbinator]

Throw a boatload of mothballs in the gas tank and enjoy.


But seriously. throw some Vette 2.5" rams horn manifolds on (if they'll clear). Dual plane manifold and maybe a 268H cam.

If I did the Vette manifolds and they did clear, would I also have to change the downpipe for the rest of the exhaust? And how much HP would that increase?

 

[Ricko1966]

If I did the Vette manifolds and they did clear, would I also have to change the downpipe for the rest of the exhaust? And how much HP would that increase?

Yes you would have to change the rest of the exhaust. And not a lot of power difference. But yes your stock exhaust is crap. If you changed out all the exhaust for better stuff,including better manifold or headers you might see 10% but it will make future mods more beneficial.

 

[Burbinator]

Yes you would have to change the rest of the exhaust. And not a lot of power difference. But yes your stock exhaust is crap. If you changed out all the exhaust for better stuff,including better manifold or headers you might see 10% but it will make future mods more beneficial.

Do my heads and Vortec heads share exhaust manifold patterns? I know intake is different

 

[Ricko1966]

Do my heads and Vortec heads share exhaust manifold patterns? I know intake is different

Same bolt pattern but vortecs have raised exhaust ports, so if you buy headers check with the manufacturer for use on vortec heads,or use vortec manifolds or gasket match your manifolds. Depending g on what gears you have now. Gears will probably be your biggest bang for the buck.

 

[Burbinator]

Same bolt pattern but vortecs have raised exhaust ports, so if you buy headers check with the manufacturer for use on vortec heads,or use vortec manifolds or gasket match your manifolds. Depending g on what gears you have now. Gears will probably be your biggest bang for the buck.

My best guess is 3.55 but I can’t be certain

 

[xm20k]

Not much you can do to a stock 350 to make more power without digging into the engine.

A set of headers, better intake, maybe larger carb up to 750, getting the tune as good as possible.

Heads and cam are going to be the biggest performance gains without digging into the rotating assembly.

Lower rear gears will make it feel more responsive from a standstill and pulling hills. Especially since you are heavier than a c10 some 3.90s or even 4.10s may feel a lot more responsive.

 

[legopnuematic]

3.42 or 3.73 for stock ratios for an 86 K1500 Burb.

3.42 was the only choice if an Auto, 4 speed manual 3.42 or 3.73

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