New Project.... need advice on motor swap

[Dutch724]

I’m not sure what I need to be asking. I’m new to the forum and to doing this project that I’m getting ready to jump into. Let me explain what I’m working with and what I would like to do, to see if I can get some good advice.
I have an 83’ K10 with a tired 305 in it. I’m unsure of the model of the tranny….. maybe turbo 350. I would like to change the motor out for a bigger motor that will handle towing with ease and run well on the street as a daily driver, but I do like a little get up and go power as well.
I have found a 97’ 5.7 vortec motor online for a decent price. Came out of a wrecked Silverado, it will need to be rebuilt just because it has over 130,000 miles on it not because it has an issue. The guy selling it has no wiring harness or brain for it. Basically he took it out of a wrecked truck at the junk yard. I would rather go this path instead of buying a crate motor for $4-5000.00. Besides I don’t mind rebuilding a motor to save me some money.
My questions begin with the wiring that I will need to have to make the motor run in my K10? Is there a much easier/cheaper way to repower this truck? When I’m done with this truck it will be going to my son when he gets out of the military.
Is there a company that will sell me all the wiring I need for the newer engine? I’m just looking for some advice and guidance. I know you all have done something of this and learned there is a better way to do it.
Should I buy the motor?
Thanks for the help.

 

[1987 GMC Jimmy]

I’m not sure what I need to be asking. I’m new to the forum and to doing this project that I’m getting ready to jump into. Let me explain what I’m working with and what I would like to do, to see if I can get some good advice.
I have an 83’ K10 with a tired 305 in it. I’m unsure of the model of the tranny….. maybe turbo 350. I would like to change the motor out for a bigger motor that will handle towing with ease and run well on the street as a daily driver, but I do like a little get up and go power as well.
I have found a 97’ 5.7 vortec motor online for a decent price. Came out of a wrecked Silverado, it will need to be rebuilt just because it has over 130,000 miles on it not because it has an issue. The guy selling it has no wiring harness or brain for it. Basically he took it out of a wrecked truck at the junk yard. I would rather go this path instead of buying a crate motor for $4-5000.00. Besides I don’t mind rebuilding a motor to save me some money.
My questions begin with the wiring that I will need to have to make the motor run in my K10? Is there a much easier/cheaper way to repower this truck? When I’m done with this truck it will be going to my son when he gets out of the military.
Is there a company that will sell me all the wiring I need for the newer engine? I’m just looking for some advice and guidance. I know you all have done something of this and learned there is a better way to do it.
Should I buy the motor?
Thanks for the help.

You'll need a distributor and carb, which you already have, but you'll also need a Vortec carb intake, and those are a little pricey relative to regular aftermarket intakes. You'll also have to do an aftermarket fuel pump because the block won't have provisions for your mechanical unit. I will say that the golden goose for a Vortec motor like that is the heads. If there's anything wrong with them, I would pass. Is this just a guy on Craigslist? If so, be careful. He may have bought it to do something similar and found that it had a cracked head or something. If not, and you know how to rebuild an SBC, I say go for it. Your truck's factory harness will handle everything once you get it set up, unless you want to go with the factory set up. I was just telling you what would be easiest. The water pumps are different between the two, and I can't recall if the flexplates are the same or not, but it's essentially the same motor improved for the nineties.

 

[Dutch724]

Everything sounds good. From what you are saying I can retro fit this motor to fit a carb on it? Is that a cheaper option or would it be better running down the electronics for the motor. Maybe that’s a mess I don’t want to get involved with? I did see the vortec carb intakes for about $600. That is still cheaper than a crate motor.
I do plan on freshening up the heads and maybe changing out the cam if that is an option. I have seen somewhere you can do a cam swap to get a little more HP and Torque on a LS or 5.3 motor, without having to rebuild the whole motor. That’s where I would be leaning.
Yeah, it’s just a guy on CL, but is $700 about the going cost on something like that? I’m not sure how he came across the motor, but he has a number of them for sale. I’m thinking he pulls them from wrecked vehicles and sells them for a little extra money. At least that’s the way he was talking about them.
I just don’t want to get in a position where I have the motor all setup and I can’t get it to work with the original wiring and gauges.

 

[CSFJ]

What crate engines are you looking at? There have been a few members on here who have sourced GM performance parts small blocks from Summit, Jegs, or their local chevy dealers (The prices seem to run fairly close to each other) for less than what you're budgeting, and possibly less than a full rebuild will cost.

 

[1987 GMC Jimmy]

Everything sounds good. From what you are saying I can retro fit this motor to fit a carb on it? Is that a cheaper option or would it be better running down the electronics for the motor. Maybe that’s a mess I don’t want to get involved with? I did see the vortec carb intakes for about $600. That is still cheaper than a crate motor.
I do plan on freshening up the heads and maybe changing out the cam if that is an option. I have seen somewhere you can do a cam swap to get a little more HP and Torque on a LS or 5.3 motor, without having to rebuild the whole motor. That’s where I would be leaning.
Yeah, it’s just a guy on CL, but is $700 about the going cost on something like that? I’m not sure how he came across the motor, but he has a number of them for sale. I’m thinking he pulls them from wrecked vehicles and sells them for a little extra money. At least that’s the way he was talking about them.
I just don’t want to get in a position where I have the motor all setup and I can’t get it to work with the original wiring and gauges.

Oh yeah, for sure. The carb setup would be a little more expensive but easier because you wouldn't have to reharness the whole engine with all that OBDII stuff. I don't think it'd be a mess if you could find a good harness, but it would definitely be an undertaking. Plus, you'd probably need to get rid of that spider injection system (CSFI) and convert it to the style that the Gen III motors use (MPFI). That alone will even the cost comparison between carbing it and keeping the Vortec system. That price is in the neighborhood of what I've seen on Craigslist. I'd pull the valve covers and looks for head cracks as best you can before you buy it, though. You won't have a problem with gauges. It's an SBC with the same ports. As far as putting an aftermarket cam in it, I believe .450 lift is the ceiling using stock style valve springs. Anything more, and you'll have to upgrade the springs. I'm not sure if we're thinking the same thing, but it sounds kinda like the LT4 cam that folks put in the Small Block Chevies.

 

[Dutch724]

GM performance and blue print engines. There is some other in there as well. You know of a cheaper place with quality motors? I would like the HP 300 or better and torque 360 or better. If I can find a decent crate motor for about $2000 I would be happy with that.

Edit:
I plan on pulling the covers off and taking a look.
All my experience with cars has been in the 70's. its been a while since I have been under the hood to try and go to the point of pulling a motor. With that being said I'm going to need some help getting up to speed on these newer motors and the electronics part of them.

 

[CSFJ]

Here's one option.

https://www.summitracing.com/parts/nal-12499529/overview/

There are other threads on here that have dicussed this at length in the last 12 months or so. I just can't recall which areas they're in atm

From jegs
http://www.jegs.com/p/Chevrolet-Per...se-350ci-300HP-Engine-Package/755609/10002/-1


And from a gm dealer page.

http://www.gmperformancemotor.com/category/SB.html

 

[1987 GMC Jimmy]

I think you could come out of the Vortec engine for about $2300-$2500 with it ready to drop in after the cam and headwork, and it'll probably make around 350-375 HP. The Goodwrench 350 is rated at 195 HP (makes up to 260), and they want $1600 plus shipping from Jegs. The weenie engines are gonna be cheaper than this proposed route no matter what. I think you'd do well if everything worked out. The good performers are gonna be at least what I'm adding up and more from there. It's up to you, though.

 

[Dutch724]

CS: That is a bunch of motor options that I didn't find before. Thx. I just don't know how 290hp with 335 torque compare with today's trucks. I'm going to have to research to see what the rating would be on pulling, mileage, and getting out of its own way. The 305 in the truck now can't even get the truck out of its own way. its severely lacking.
I'm learning as I go.

GMC: With me building the motor myself it would cost roughly the same amount, but would I be putting better parts in the motor? well, not so much "better" per say, but higher producing parts. Now, I don't want a lope or have to use 91 octane gas. I want to be street friendly like a daily driver.

You guys have given many options to think about and I appreciate that. Once I finish this Seadoo motor I will be ready to tackle the K10.

 

[1987 GMC Jimmy]

CS: That is a bunch of motor options that I didn't find before. Thx. I just don't know how 290hp with 335 torque compare with today's trucks. I'm going to have to research to see what the rating would be on pulling, mileage, and getting out of its own way. The 305 in the truck now can't even get the truck out of its own way. its severely lacking.
I'm learning as I go.

GMC: With me building the motor myself it would cost roughly the same amount, but would I be putting better parts in the motor? well, not so much "better" per say, but higher producing parts. Now, I don't want a lope or have to use 91 octane gas. I want to be street friendly like a daily driver.

You guys have given many options to think about and I appreciate that. Once I finish this Seadoo motor I will be ready to tackle the K10.

With the Vortec, yes. The heads are arguably the best performing GM factory SBC heads. When you put in your better cam, that too. They have the L31 Vortec long block on Jegs for $2,069, but you'd still have to source the intake and cam, and you'd be over that $2500 point with that. However, you'd have your Vortec already built for you, and if you played your cards right, you wouldn't be that much over. I'd suggest looking for the intake on eBay or Craigslist to see if you can score a deal there. The Vortec setup with a mild or moderate cam is gonna be a pump gas motor.

 

[HotRodPC]

....with a tired 305!?!?!

Wee O Fives are tired at birth from the factory and right off the showroom floor.

 

[1987 GMC Jimmy]

Me? I was talking about the 350.

 

[HotRodPC]

I was quoting OP's original post without quoting the whole thing. He said he has an 83 blah blah blah with a tired 305....

 

[justin71105]

I am in sort of the same boat, got a 305 that is lacking in power and want to drop in a Vortec crate engine. I am going with the L31-R from summit and this intake/carb kit.

https://m.summitracing.com/parts/cmb-03-0197/applications?prefilter=1

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[Honky Kong jr]

....with a tired 305!?!?!

Wee O Fives are tired at birth from the factory and right off the showroom floor.

I got 1 worse ok 2 the 4.3v8 and the 260 Olds holy slug Batsman.