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engine combo question

beater_k20

beater_k20

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i'm looking at a 79 K20. the price is right, the body and drivetrain are decent, but it needs a motor. i was tossing around some combos using my Vortec 5.7 as a base. the Vortec needs a crank kit, and a new set of rods. so, i might as well go 383, since i planned on boring it anyways. the combo i cam up with (according to DD2K) makes around 350 hp @ 4500-5000 rpms. the torque curve is as flat as i've ever seen one, running 450-460 ft/lb from 2000(lowest the scale goes)-4000. since i'm planning on using this truck for temporary DD status, and pulling my derby truck to the shows, i think that will be just fine backed by a 465/205, 14FF with 4.10s on 33s. the combo is:4.030" bore 3.75" stroke 383 cistock Vortec heads8.85:1 SCR (around 7.6:1 DCR 87 octane friednly )Comp XR 258 cam 258/264 adv dur, .480/.487 lift (valve guide cutting required)Q Jet and a Performer intake, small tube headers, and 2 1/4" dual exhaust.i'm also considering sacraficing this truck after its built to save my 77 K20 from its current life of plowing snow, and hauling trash. as you all may know, my plans for it are a frame off restoration/modification in memory of my grandfather.my question is do any of you with plowing experience think that this kind of power would be acceptable in a plow truck? FWIW, building the 383 will only be a few hundred dollars in machine work more than buying a crate engine with significantly less towing power. plus the knowledge of whats actually in there,rather than never seeing the inside of the engine.
 
383's rock for low revving stump pulling torque. Just dont try n hit 7,000RPM in one. I say do it. Ive had 383's in 3 vehicles. Next time I may go stroked 400!! The combo sounds good. Vortec's are good cheap heads. And its a mild motor that revs low so it should last quite a while and be reliable.
 
engine builds always add up, I'd expect you to know that. I figured I could do my 383 cheap, that was stupid of me.

Sounds like a killer combination to me. THrow a slightly more midrange cam in it and you have what I built myself for my trail toy. Well different heads but with the port work done to them I'd bet they'd stand along side a set of Vortecs.
 
only a couple things that i didnt take into consideration... pumps, oil, water, fuel. misc sensors, rodding the radiator, little stuff like that, which would be the same price as going with a crate.
 
Just a thought, I know its more complex, but what about an LS motor?

I'm just thinking at this point thats the way to go anymore. The power and driveability from a stock one is amazing compared to old motors, or most you build.
 
dyeager535 said:
Just a thought, I know its more complex, but what about an LS motor?

I'm just thinking at this point thats the way to go anymore. The power and driveability from a stock one is amazing compared to old motors, or most you build.
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i already have an L31 Vortec longblockblock sitting in my garage, and i'm planning on keeping it carbed for now. maybe look into a TPI setup later. the LS motor would cost me at minimum the same amount i'll have into the 383, not make as much usable power, plus i'll have to deal with the wiring and completely rework the fuel system. just doesnt make sense for me to go that route. if i was thinking of some wacky idea of an engine, then maybe i could see it. with something this basic that easily fulfils my needs and then some, the LS engine is pretty pointless to me.
 
LS1's make more power in the upper RPM, and wont get the low down torque a 383 will make. Plus you'd have to wire it up. Would be cool in a resto-mod car.
 
I think if you look at the torque "curve" of the LS motors, you might be a bit surprised.

I'm not arguing that it is possibly underpowered for a tow rig on the low end (especially compared to a larger displacement engine) but the amount of overall power on a bone stock LS motor makes the gen1's look stupid.

Again not a tow rig application, I just know that for what it ended up costing me in build, an LS motor makes *mine* look pathetic. As beater mentioned, going to be less carbed than mine was with TPI. But I too started out with the "L31" (no roller stuff though) idea and ended up TPI...LS off the bat would have saved me time and money. Any port injection swap with Vortec heads (short of a Vortec swap) is going to be expensive.
 
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