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Old 02-03-2016, 09:05 PM   #1
BlackedoutC10
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LT1 Vs 5.7 Vortec?

Looking to start building a motor for my 83 c10. I have two options available right now one a 1999 suburban with a 5.7 vortec and just today a friend told me he has an lt1 motor out of a 1995 z28 and may be interest in a little AK 47 swapping for it.

I don't know anything about building motors and nothing about swapping them. This is going to be a good learning experience for me and i'm not planning to rush it (The original 305 is still running fine). What would the pros and cons of these two motors be and is one a better/cheaper motor to work with then the other.

Down the road id like to be able to maybe turbo the truck and just have something fun to drive but reliable. Id also like the have the gas mileage above 16-17 mpgs.

Any tips or suggestions appreciated! Thanks
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Old 02-03-2016, 10:20 PM   #2
65standard
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Re: LT1 Vs 5.7 Vortec?

Between those two, I would go with the LT1. The 5.7 vortec is just a gen I small block chevy.
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Old 02-03-2016, 11:16 PM   #3
BlackedoutC10
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Re: LT1 Vs 5.7 Vortec?

Thanks 65standard. I've been looking around for the last 2 hours at the 5.3 vortec swaps and have found a few motors with wiring and everything from bowauto on ebay for between 1500 to 1700. Thats not much more than ill have in the LT1 starting out. (may be worth it?)

Although from reading around the web it seems to be a lot more work/money getting the 5.3s in vs the LT1 or 5.7. The extra work doesn't scare me but I am concerned about the amount of money it will cost to just get it put in. Estimates i've seen are around $800 in extras to put a stock 5.3 into a c10 , can anyone who has completed this swap confirm that?
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Old 02-04-2016, 01:59 AM   #4
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Re: LT1 Vs 5.7 Vortec?

I had an LT1 in a 1995 Caprice Station wagon. It will bolt in where ever a small block will, but it has different heads and a distributor mounted on the front of the engine, where water can splash on it, and short it out. It was a good, powerful last hurrah for the small block chevy before the LS engines came out. The LS engines are worth it. The LT is kind of obsolete now. The LT1 got pretty good mpg in my wagon...but unless it's free, i would go with an ls, or if i wanted to get on the road quickly and for less $, just a plain old small block.
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Old 02-04-2016, 06:05 AM   #5
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Re: LT1 Vs 5.7 Vortec?

The good optispark have a vent hole in them in case the water pump leaks.To me it depends how many miles are on both engines and what shape they are in.
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Old 02-04-2016, 06:30 AM   #6
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Re: LT1 Vs 5.7 Vortec?

I would prefer the vortec.. you could swap in a newer PCM (0411 PCM) easily and give yourself some tuning options with it. Also you lose the somewhat problematic optispark dizzy on the LT1. Vortecs have their set of problems too, (intake gaskets, plastic dizzy housing, injector spider), but those are easily fixed. I think there is more performance potential with the Vortec, IMHO
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Old 02-04-2016, 06:32 AM   #7
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Re: LT1 Vs 5.7 Vortec?

Quote:
Originally Posted by 65standard View Post
Between those two, I would go with the LT1. The 5.7 vortec is just a gen I small block chevy.
LT1 is just a small block chevy too.....with a bunch of weird stuff
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Old 02-04-2016, 12:23 PM   #8
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Re: LT1 Vs 5.7 Vortec?

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Originally Posted by wildwilly4x4 View Post
LT1 is just a small block chevy too.....with a bunch of weird stuff
92-96 LT1 and LT4 engines were known as Gen II. They were essentially small blocks with aluminum heads, reverse coolant flow, and Optispark. The LT1 was rated at 275 (Camaro) or 300 (Corvette) net hp, as I recall, and pulled like a freight train off-idle to 5,500 RPM. They seemed to have lots of problems related to the Optispark, which were apparently resolved in the 95 model year.

The 5.7 Vortec is a truck engine with an emphasis on lots of low-mid RPM torque. Rated horsepower was 250, as I recall. So in stock form, it will be more of a torquer than a revver. However, the Vortec heads with different springs will probably support more power than than LT1 heads.

Both engines have roller cams, so you can have the best of both worlds -- good idle and wide power band, along with no worries about cam lobe failure.

I'm not an EFI guy, but do your homework to learn what's required in the way of electronics, fuel pump, O2 sensor, etc. You'll also need a return line to the fuel tank.
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Old 02-04-2016, 02:58 PM   #9
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Re: LT1 Vs 5.7 Vortec?

Just for the record. The vortec cylinder heads were patterned right from the LT1 design. The only major difference is the reverse flow cooling on the LT1 head. Otherwise port configuration and dimensions are virtually identical and they flow decent for a stock Gen1 style 23 degree head.

That's the reason why the vortec heads have worked so well on performance builds and why hotrodders use them. You can thank the LT1 engineers for that.

Nothing about either engines architecture would lead me one way or the other. I've swapped a couple of LT1's, one of them in my wife's Scrambler, and owned another 97 Z LT1. I never had any issues with any of them, they run strong and crisp.

What would make me lean one way or the other on your swap with the 2 choices given is how much money you're willing to spend and the availability and knowledge of tuning software or the lack there of. I sold all my LT1 tuning software because I figured I'd never own another one. I jumped on the LS bandwagon for a while and switched to HPtuners, (they don't support LT1's)
Another consideration is what you might want to spend on wiring harnesses. I use Howell for all my swaps, plug and play, all brand new stuff. No worries hacking up 15-20 year old harnesses that are already questionable. These multiport fuel injection swaps can get expensive, not to mention upgrading the fuel system to support it. If you wanted to keep it simple and cheap, I'd throw a carb on the vortec engine and run with it. I don't much care for the throttle bodies and the lack of decent computer software and the ancient computer that runs it, not to mention there isn't a lot of HP potential with them. It can all be updated but that's more money, may as well start with a more modern setup from the get go. Anymore I shy away from it all and only do them for customers if requested. Myself, I'm back to carbs and simplicity.
My personal choice since both of your engine choices have outdated hardware, I'd hold off for an LS, there is much more support for them right now. You'll spend more money, but I think you'll be happier in the long run.
If you're dead set on running the LT1, I'd invest in the computer that comes tuned along with a harness from Howell. That way the computer is ready to rock and you won't have to search long and hard to find a tuner that still messes with LT1's. I know pickin's are slim for LT1 tuners around here, most shops dropped them years ago.
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Old 02-04-2016, 03:09 PM   #10
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Re: LT1 Vs 5.7 Vortec?

Quote:
Originally Posted by MikeB View Post
I'm not an EFI guy, but do your homework to learn what's required in the way of electronics, fuel pump, O2 sensor, etc. You'll also need a return line to the fuel tank.

This^^^^.... To set up the fuel system properly for a high pressure EFI I highly recommend an in-tank pump setup. Don't go the cheap route with an in-line pump like so many do. The life of an in-line pump is short, they run hot, eventually leaving you stranded without much warning. I've never gotten more than about 6-8,000 miles out of them on daily drivers. Ultimately, making the switch to an in-tank system like the OEM uses is the best route.
You'll either need a Tanks-Inc fuel tank designed for in-tank pump or possibly find one that fits from another fuel injected vehicle. If not then the only other way I'd go is the stealth pump from Aeromotive that encases the pump inside your original tank.
If you do a system properly, by the time you run new lines, a return, regulator, pump setup, new tank, you can quickly shove $600-$1000 in a fuel system alone. This is usually enough to shy away most people from a fuel injection swap.
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Old 02-04-2016, 07:45 PM   #11
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Re: LT1 Vs 5.7 Vortec?

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Originally Posted by 65standard View Post
Between those two, I would go with the LT1. The 5.7 vortec is just a gen I small block chevy.
The LT1 is just a vortec 350 with reverse flow cooling and stupid ignition.

Go vortec. Much easier to put in, able to make just as much power as the LT1 [same exact ports in the heads, and aftermarket there are a million more options for heads on a GEN1 vs LT1]. If your going to go threw the bother of swapping a fuel injection system, then put a LS based engine in.
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Old 02-04-2016, 08:41 PM   #12
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Re: LT1 Vs 5.7 Vortec?

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Originally Posted by Firebirdjones View Post
Just for the record. The vortec cylinder heads were patterned right from the LT1 design. The only major difference is the reverse flow cooling on the LT1 head. Otherwise port configuration and dimensions are virtually identical and they flow decent for a stock Gen1 style 23 degree head.
I stand corrected.

Quote:
Originally Posted by Firebirdjones View Post
Myself, I'm back to carbs and simplicity.
I went with a Weiand 8121 manifold and Holley 600 CFM carb on the 350 Vortec engine that I installed in my 82 C10. The engine has a little higher compression (block was decked .020") and a GM 196/206 roller cam as used in the RamJet 350 and HT383 crate engines. Idle is smooth, vacuum is 20", and the torque delivery gets the truck moving in spite of its 2.73 axle.

I'm also running 96-up cast iron exhaust manifolds from the 96-up Vortec trucks, but wondering if I left some usable power on the table by not using headers. Comments?
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1982 C10 SWB -- sold
1981 C10 Silverado LWB -- sold, but wish I still had it!
1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming.
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Last edited by MikeB; 02-04-2016 at 08:59 PM.
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Old 02-04-2016, 11:50 PM   #13
BlackedoutC10
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Re: LT1 Vs 5.7 Vortec?

Thanks for all the input guys!

AndrewMP6. Vortec 5.7 has 212k its a 4x4 suburban I hope to get a year of winter driving out of and then rebuild for my c10 ($1300 to $1500 for whole suburban). LT1 is unknown but says it was lower 100k-110k maybe? (Swap AK 47 and some cash not sure how much cash he wants yet)

MikeB Both seem to fit what I want if they are low to mid torque. I want something that will get up to speed pretty quick and be fun to drive red light to red light so to speak. I would like to be able to get around traffic at highway speed if I need to also.

Firebirdjones I had no idea the fuel system was going to get that pricey to go fuel injected, that's definitely making me rethink things alittle. I wanted to get the reliability of fuel injection but I guess I cant say my quadrajet has let me stranded yet.

Seems most are swaying the vortec route and a few have mentioned just putting a carb on the 5.7. So to save alittle money on fuel system and wiring harness what would be differences between a carbureted 5.3 or 5.7. From my understanding the 5.7 may be alittle easier to put in but would the 5.3 be worth the little extra work in the long run?
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