73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 74chev4x4 on November 17, 2010, 05:37:54 pm
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I'm going to be buying a new 350 for my truck in the next couple of weeks and have narrowed it down to two motors. The Goodwrench 350/260 hp motor or the L31 vortec. My question is how is the L31 a better motor(I know it has the vortec heads and it flows way better) it is rated at 330 hp and 325 torque and the goodwrench 260 hp has 350 ft lbs torque. Isn't torque better for a truck motor and it seems the goodwrench 260 has more torque? I am open to spending more on the vortec motor, but just wanna make sure it will be something that is worth spending the extra coin on and will have more power for my 3/4 ton truck. Wanting to be able to pull a little and possibly put a camper on the truck so I believe I need torque over hp for this? Any help would be great guys, thanks.
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L31 all the way! Lol
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Why though? The cheaper non vortec is better on up and torque or am I mistaken.
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With the Vortec you have the capability to increase HP and Torque much easier than with the Other motor.
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Anyone know what headers and edelbrock performer intake will bring the numbers to on the l31.
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There is no such crate offering for a 350 vortec engine that makes 330 hp and 325 ft-lb. The GMPP 330hp crate you must be referring to is also rated at 380 ft-lb of torque. If you compare two engines with the exact same components except one has 882-style heads and the other has Vortec heads, the Vortec headed engine will make more torque throughout the power band.
Don't be swayed by peak torque numbers. The important thing to consider is which engine makes more torque in an rpm range YOU use the most.
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Well I have a Turbo 400 so I will be in a little higher rpm, yea I saw that I messed up on the initial hp of the vortec its 255 hp. So u guys would spend a little more and get the l31?
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For a crate, yes, I think the L31 would be worth it. you're getting far better heads, better block, and a hyd roller cam, for about $500 more. With a good intake, a well tuned carb, headers, and a free flowing exhaust it will make significantly more than 255 hp and 330 ft-lbs. That L31 rating was achieved with log-style exhaust manifolds and a somewhat restrictive intake. The (commonly accepted) Goodwrench rating of 260/350 was achieved with headers, free flowing exhaust, and a performer intake. If given that same components, a the L31 will trump the Goodwrench in terms of torque.
Be sure to shop around when buying a GM crate. You should even check with your local Chevy dealers. When I bought my crate, it was a local dealer that offered me the best deal. I was shocked.
http://paceperformance.com/i-5134969-12530282-5-7l-l31-r-1996-2000-chevy-gmc-full-size-trucks-1996-2002-g-van-savannahexpress-vans-under-8600-gvw.html
**There are a two "gotchas" that come to mind with this crate that you should consider. It has no provision for a mechanical fuel pump, so you'll need an electric pump. Also you will require a flexplate designed for a 1-piece rear seal crank.
BTW what is your current engine combination? Is it completely inadequate or do you just want a little more?
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Sorry if my comment was kind of bland lol. The better heads and roller cam among other things like others stated will benifit you more.
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no it made sense, I just wanted to know what the benifits were of this motor over the stock goodwrench 350. So I will need a vortec intake, electric fuel pump and a new gear for the dizzy right? Everything else will swap over from my old 350? Thanks.
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Everything as in all the belt driven stuff? Then yes they should.
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well yea and like headers and motor mounts and all that stuff, should cause its still gen 1 small block right.
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also will my 600cfm edelbrock 1406 carb be enough for the L31.
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Anyone here running the l31 in there truck with a Carb if so how do u like it, big difference over stock 350 and how is gas mileage?
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I'd go vortec and 600cfm will be plenty.
Basically All the external engine pieces swap back and forth except for the intake manifold, valve covers, and flexplate, timing cover, dipstick.
Don't know first hand about old style heads vs L31 heads, but I've read enough about them and the good of the vortec heads, that I'm going to put vortec heads on my engine when the time comes.
The vortecs actually swirl the fuel mixture into the cylinder andthe way the chamber is setup is burns the mixture faster. I'm actually told that engines with vortecs take less total advance too. Vortec heads have a bit larger intake runners (170cc) but they have a venturi in the runner to accelerate the incoming fuel mixture into the cylinder. As far as I can tell and read, vortecs are the best heads Chevy ever put on a production engine.
The biggest deciding factor on gas mileage will be how well you have your carb tuned. from my experience, none of the new carbs I have had were setup just right for my engines. You'll have to play with the jets and rods and such until you get most power, also have to play with the timing and start out at stock settings but adjust it from there how it runs best.
In my 350 with a 1406, I've Kept the power mode as base setting but made the cruise setting 1.5 stages leaner. also I've gone up 2 sizes in the secondary jets. and one level higher rod springs. This is on a bone stock engine. The settings would very likely be different with vortec heads.
With that and light throttle, I'm getting 16-17 mpg under 60mph with a light foot and a 5000lb truck with old style heads.
The point being, just you'll have to play with it until its setup right, as its extremely rare for a carb to come setup just right for a given engine. Also before you put that carb on anything, check the floats level as every one I've ever seen was off some right out of the box.
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There is one more thing that I feel is worth mentioning. The L31 engine has about 9.5:1 static compression and a when combined with a very small cam means fairly high dynamic compression. And while the vortec heads promote faster combustion, require less ignition advance, and are more octane friendly, that compression may still be too much for 87 octane in your application. I cannot say for sure. These engines only called for 87 octane in their original applications, but they also had the advantage of knock sensors and electronically controlled ignition timing to keep them safe under high load conditions. If potentially running 89 or higher octane is an issue for you, you may wish to hear from someone who has run this particular engine on 87 successfully.
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Thanks guys really good info, I was wondering about the compression and octane gas, anyone run this motor on 87 with any problems?
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anyone have suggestions of what intake would be best for this L31 motor, matching the intake with where the motor makes its best torque powerband? I'm looking but its a little confusing.
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Low-rise dual-plane.
USA made: Summit Racing 226018 (summitracing.com $130), Edelbrock 2116 (flatlanderracing.com $155), Weiand 8121 (summit $166), Edelbrock 2716 (summit $185)
Chinese made: Professional Products 52007 (summit $140)
*I am fairly certain the summit intake is a rebranded Weiand intake. Compare them and I bet that aside from the logos, you can't tell the difference. I can't. Call summit and confirm. It looks like the sweetest deal.
**The Summit, Weiand, and more expensive Edelbrock manifolds are square bore to work with Holley or Edelbrock carbs only. The other two are spreadbore, which work with Q-jets and squarebores.