LS vs Vortec Swap vs Basic Upgrades - Cost Factors

[Doppleganger]

My K20 needs upgraded - only deciding factor now is cost. I think to rebuild an LS or a Vortec either one is probably a wash cost wise, but the 'little' things are what add up fast. I dont want to drop anything in without really checking it out / opening it up. I had a 77k motor once that I dont think the oil had been changed twice. Looked immaculate on the outside - inside, not so much. I remember using Gunk Flush in it and when we drained it out it looked like we were giving the car an enema - large blobs of sludge. Stuff like that. Also had a 113k motor that burned a qt every 100 miles.....when we opened it up, the cylinder walls looked like chrome - my tech buddy guessed someone used an additive or something and the rings never seated properly. Dunno.

The 6.0 LS I found has 142k on it. I suppose it would be ok as-is.....but what about the coil packs? Or the harnesses? Or the ECU that will need flashed? These are the expenses I know can blindside a project and leave me with the GDP of a small country tied up in a truck thats not running. Bad juju.

Also found a 98 Vortec 5.7 with 150k. Could keep it carb'd for the time being til I sell a kidney or something to buy a TBI setup.

My Plan C is to source a reman set of Vortec heads, add an Edlebrock performer intake, maybe a better cam and use the stock 350 as-is.

Just thinking out loud - wondering what you fellas have encountered with your own swaps / upgrades. I searched and read quite a bit but $$$ figures aren't mentioned as much. It also needs totally rewired badly so alot of what happens under the hood will affect that as well.

Thanks in advance.

 

[Shorty81]

Stroke your 350. Or maybe a big block. JMO, I would not put a modern engine in an old Chevy.

 

[Camar068]

best thing to do is start a spreadsheet with a line item for everything. Research each one and put a cost next to it in a "projected" column.

 

[shiftpro]

You might have a challenge finding used Vortec heads that are NOT cracked, but there are aftermarket cast iron Vortec copies for sale.

 

[1987 GMC Jimmy]

I would say no to anything Gen III (“LS”). I’d be interested in what different bolt ons (heads, intakes, headers, hotter coils, cams and timing sets, higher stall torque converters, shorter gearing, stroker kits, and performance carbs or aftermarket EFI would do. This includes what Gen II (“LT”) parts would do on a higher performance carb setup both in terms of desired performance and cost. Vortec heads, too. I don’t know if you’re thinking about going the whole way on a Vortec setup, and while it doesn’t offend me in principle, I wouldn’t want to mess with all the wiring when you can have great performance without it.

 

[4WDKC]

LS swap it the sloppy turbo guys are beating those stock engines with 15 psi with 200k+ miles on them. keep it stock and you will only need features disabled.

 

[Doppleganger]

After finding my stumbling under acceleration problem was the fact that it did not have a 650 on it as advertised but instead a 390. I doubt it was enough carb for the motor.

For cost purposes, I'd probably lean towards just a nice set of Vortec heads with an Edlebrock intake and carb. I've got stainless long tube headers I have never installed either - this was a left coast truck with Cali emissions (exhaust manis that look like paper towel rolls - that cant help any power wants/needs). Maybe a better cam? An actual Vortec block (with a roller cam) would be even better.

I really hate doing things twice and would love to go all in on something that gets great mileage and more power - but the LS's (from what I have seen and heard) can get expensive fast. Also the issues of dual tanks with the LS.

Thanks for the input fellas.....


4WDKC.....what color is your Vette? Thats an awesome pair of rides there.

 

[77 K20]

I'll throw my 2 cents in here. You might not like how a vortec head equipped engine acts in the winter. GM designed them to be used with a dry manifold (no suspended fuel in the air) and so the engine design keeps the intake manifold nice and cool.

If winter driving doesn't apply to you then don't bother reading the story below of my hard earned lesson about my engine.

The older GM engines had a heat crossover under the intake to heat it. Bad for performance, but great in winter. A warm intake keeps the fuel droplets suspended in the air stream.

I had only read about all the advantages of the vortec heads and ended up buying a GM crate motor with the vortec heads. Ran awesome the summer I put it in. Then fall came by- why is it running a bit rough after starting it? Then winter time... why it is misfiring when I first start it? Why is it bogging down and needing to be cleared out then will finally run fine 15 minutes later?

FINALLY after reading for months I found out at temps of about 38 degrees and below the intake was too cold. (And keep in mine that my engine has 21" of vacuum at idle. Air temps cool even more in a vacuum). After the air goes straight down thru the carb/TBI it needs to make a 90 degree turn. When the manifold is cold it will drop out of suspension and start forming a puddle. Then when I'd rev it the puddle would get sucked down into some cylinder and it would run better for a few seconds and the puddle would reform. The GM performance manifold they used was very smooth under the carb/tbi. This is a bad thing. Older manifolds have either a waffle pattern or just a bunch of "speed bumps" cast into it. These ridges help get the fuel suspended again. A puddle will form but when it tries to flow up and over the ridge it will lose grip on the manifold and be carried off by the air again.

It will depend on what type of driving you do on how quickly it would warm up. In my case I go about 1/8 mile then highway (65 mph) for 9 miles and then there is a stoplight. Still sputtering at that light. Why? Cold air coming into the engine at 3000 RPM at highway speed kept the intake manifold very cold. It would then warm up eventually going thru some more lights in town.

So I bought an Edelbrock 7116 manifold. Checkerboard pattern inside the manifold. Provisions for a heat plenum under the carb/tbi. I plumbed the coolant bypass (big subject for another debate... vortec heads need a coolant bypass) thru this heat plenum. It still sputtered a little bit for the first minute or two but once any heat got into the coolant the intake warmed up a little- and ran fine.

Problem solved... no. Started losing coolant. Not dripping anywhere. Thought it was the good intake manifold gaskets. Replaced those. Same issue. It was still drinking 700 mL every week. I finally pulled the tbi and looked down into the manifold. The waffle pattern had little puddles of coolant. It must have a porous casting and the coolant was leaking thru and being burned off. Edelbrock was NO support at all. Denied it could even happen. Without anything better to try I bought another 7116 (thinking that I had the only defective intake manifold ever made in this universe) and installed that one. SAME ISSUE. At this time I was ready to blow up the whole truck or drive it off a cliff.. fireball... so I dumped in some alumniseal crap (radiator stop leak for aluminum parts) then switched out my 16 lb radiator cap for a 7 lb? 8 lb? and been running like that for 3 years. The first 60-120 seconds it sputters a little bit then after that it is fine.

Is this proper? No. Did I get the only 2 defective 7116 manifolds around? Maybe. They say you can port exhaust thru the heat plenum instead. That might be better... but couldn't figure out a good way to do that.

You must be registered for see images attach

waffle pattern

You must be registered for see images attach

waffle pattern with coolant "sweating" thru the aluminum and forming little puddles

You must be registered for see images attach

the hose under the PCV tubing is the coolant bypass that puts coolant under the carb/tbi

You must be registered for see images attach

the stock GM manifold. No waffle pattern

If I was to go back and try it all over again I'd still keep for vortec heads but would have tried the Edelbrock Pro-flo multi port injection manifold/system. This is pretty much the same as what GM used from the factory. A dry manifold that uses an injector at the last second before the cylinder itself.

Sorry for the book- this issue cost me a lot of time and money. Figured others should laugh (or maybe learn?) at my expense.

 

[1987 GMC Jimmy]

I'll throw my 2 cents in here. You might not like how a vortec head equipped engine acts in the winter. GM designed them to be used with a dry manifold (no suspended fuel in the air) and so the engine design keeps the intake manifold nice and cool.

If winter driving doesn't apply to you then don't bother reading the story below of my hard earned lesson about my engine.

The older GM engines had a heat crossover under the intake to heat it. Bad for performance, but great in winter. A warm intake keeps the fuel droplets suspended in the air stream.

I had only read about all the advantages of the vortec heads and ended up buying a GM crate motor with the vortec heads. Ran awesome the summer I put it in. Then fall came by- why is it running a bit rough after starting it? Then winter time... why it is misfiring when I first start it? Why is it bogging down and needing to be cleared out then will finally run fine 15 minutes later?

FINALLY after reading for months I found out at temps of about 38 degrees and below the intake was too cold. (And keep in mine that my engine has 21" of vacuum at idle. Air temps cool even more in a vacuum). After the air goes straight down thru the carb/TBI it needs to make a 90 degree turn. When the manifold is cold it will drop out of suspension and start forming a puddle. Then when I'd rev it the puddle would get sucked down into some cylinder and it would run better for a few seconds and the puddle would reform. The GM performance manifold they used was very smooth under the carb/tbi. This is a bad thing. Older manifolds have either a waffle pattern or just a bunch of "speed bumps" cast into it. These ridges help get the fuel suspended again. A puddle will form but when it tries to flow up and over the ridge it will lose grip on the manifold and be carried off by the air again.

It will depend on what type of driving you do on how quickly it would warm up. In my case I go about 1/8 mile then highway (65 mph) for 9 miles and then there is a stoplight. Still sputtering at that light. Why? Cold air coming into the engine at 3000 RPM at highway speed kept the intake manifold very cold. It would then warm up eventually going thru some more lights in town.

So I bought an Edelbrock 7116 manifold. Checkerboard pattern inside the manifold. Provisions for a heat plenum under the carb/tbi. I plumbed the coolant bypass (big subject for another debate... vortec heads need a coolant bypass) thru this heat plenum. It still sputtered a little bit for the first minute or two but once any heat got into the coolant the intake warmed up a little- and ran fine.

Problem solved... no. Started losing coolant. Not dripping anywhere. Thought it was the good intake manifold gaskets. Replaced those. Same issue. It was still drinking 700 mL every week. I finally pulled the tbi and looked down into the manifold. The waffle pattern had little puddles of coolant. It must have a porous casting and the coolant was leaking thru and being burned off. Edelbrock was NO support at all. Denied it could even happen. Without anything better to try I bought another 7116 (thinking that I had the only defective intake manifold ever made in this universe) and installed that one. SAME ISSUE. At this time I was ready to blow up the whole truck or drive it off a cliff.. fireball... so I dumped in some alumniseal crap (radiator stop leak for aluminum parts) then switched out my 16 lb radiator cap for a 7 lb? 8 lb? and been running like that for 3 years. The first 60-120 seconds it sputters a little bit then after that it is fine.

Is this proper? No. Did I get the only 2 defective 7116 manifolds around? Maybe. They say you can port exhaust thru the heat plenum instead. That might be better... but couldn't figure out a good way to do that.

You must be registered for see images attach

waffle pattern

You must be registered for see images attach

waffle pattern with coolant "sweating" thru the aluminum and forming little puddles

You must be registered for see images attach

the hose under the PCV tubing is the coolant bypass that puts coolant under the carb/tbi

You must be registered for see images attach

the stock GM manifold. No waffle pattern

If I was to go back and try it all over again I'd still keep for vortec heads but would have tried the Edelbrock Pro-flo multi port injection manifold/system. This is pretty much the same as what GM used from the factory. A dry manifold that uses an injector at the last second before the cylinder itself.

Sorry for the book- this issue cost me a lot of time and money. Figured others should laugh (or maybe learn?) at my expense.

I know you posted about this issue a few years ago, but what air cleaner are you using? It looks like you have exhaust manifolds and not headers. The stock Thermac unit with the heat stove and riser intact to suck in warmed air might help. Not as proximal as the actual crossover, but I’d say it’s the next best thing.

 

[4WDKC]

After finding my stumbling under acceleration problem was the fact that it did not have a 650 on it as advertised but instead a 390. I doubt it was enough carb for the motor.

For cost purposes, I'd probably lean towards just a nice set of Vortec heads with an Edlebrock intake and carb. I've got stainless long tube headers I have never installed either - this was a left coast truck with Cali emissions (exhaust manis that look like paper towel rolls - that cant help any power wants/needs). Maybe a better cam? An actual Vortec block (with a roller cam) would be even better.

I really hate doing things twice and would love to go all in on something that gets great mileage and more power - but the LS's (from what I have seen and heard) can get expensive fast. Also the issues of dual tanks with the LS.

Thanks for the input fellas.....


4WDKC.....what color is your Vette? Thats an awesome pair of rides there.

Vortec heads, with machine work needed and valve springs, intake manifold, cam, all gaskets and fluids cost about $1000.. I did the swap 2 years ago then I still had a tired 350 that was leaking oil from the RMS, a stock 700r4.. A friend bought a wrecked 4.8 2wd truck for $650 and swapped it into his big body pontiac reusing everything he could. He paid $75 to have the stock ecm tune out the ABS, rear ot etc stuff not needed for the swap, ac relocation kit $200, engine mounts, redid the harness himself, reused the stock fuel pump, he bought some plastic fuel lines to connect to the stock rails like ti was factory. All said and done he has less than 2k in the swap... if you can find a wrecked 5.3 4x4 you could do the same, I would.

Thanks, sold the truck in Dec. when I moved to Florida, not sure what color the car is its not stock and closest we could find was 2011 Kia color.

 

[Doppleganger]

77 K20 - info like that is priceless....stuff you'll never read about in a tech manual. A few years ago I dealt with aluminum blocks that had porosity issues - would find AF leaks in places there was nothing to leak from. This went on for 3 1/2 model years before the manufacturer did something about it....probably took that long in warranty beatings to prod them along. I dont run the truck in the winter much.....it has never seen salt - will keep it that way for as long as possible. Was looking at the 2116 intake a long time ago - was told by an old gear head that was the best one he had tried.

Vortec heads, with machine work needed and valve springs, intake manifold, cam, all gaskets and fluids cost about $1000.. I did the swap 2 years ago then I still had a tired 350 that was leaking oil from the RMS,

Thats about the same $ amount I was coming up with - also sounds like the same motor I have (100k so not terrible). I bagged a yr old Holley 650 (still dont like them but my fuel lines have been bastardized to fit one, and the carb was already being used on a 350) for cheap so should take care of the stumble part. I've been contemplating pulling the motor out and replacing all the seals, cleaning it up, replacing the water pump and timing chain, etc. when/if I swap all this over. Gets it at least usable til something more drastic takes place. Gotta get rid of those stock exhaust manifolds too.

 

[SquareRoot]

best thing to do is start a spreadsheet with a line item for everything. Research each one and put a cost next to it in a "projected" column.

And then multiply it by 4.

 

[Jrgunn5150]

If you're just stuck on keeping the Gen 1, then a Vortec take out is the way to go, IMO. They ran with spark and fuel control in overdriven applications. Very little wear or soot in them usually.

If you just can't slap in a junkyard engine and roll, then you may as well rebuild the one you have, since you already know you have the little thing's you need.

A LS swap, on a 4x4, with all new everything just cuz... Is going to add up to more than the truck is worth.

 

[SquareRoot]

I'll throw my 2 cents in here. You might not like how a vortec head equipped engine acts in the winter. GM designed them to be used with a dry manifold (no suspended fuel in the air) and so the engine design keeps the intake manifold nice and cool.

If winter driving doesn't apply to you then don't bother reading the story below of my hard earned lesson about my engine.

The older GM engines had a heat crossover under the intake to heat it. Bad for performance, but great in winter. A warm intake keeps the fuel droplets suspended in the air stream.

I had only read about all the advantages of the vortec heads and ended up buying a GM crate motor with the vortec heads. Ran awesome the summer I put it in. Then fall came by- why is it running a bit rough after starting it? Then winter time... why it is misfiring when I first start it? Why is it bogging down and needing to be cleared out then will finally run fine 15 minutes later?

FINALLY after reading for months I found out at temps of about 38 degrees and below the intake was too cold. (And keep in mine that my engine has 21" of vacuum at idle. Air temps cool even more in a vacuum). After the air goes straight down thru the carb/TBI it needs to make a 90 degree turn. When the manifold is cold it will drop out of suspension and start forming a puddle. Then when I'd rev it the puddle would get sucked down into some cylinder and it would run better for a few seconds and the puddle would reform. The GM performance manifold they used was very smooth under the carb/tbi. This is a bad thing. Older manifolds have either a waffle pattern or just a bunch of "speed bumps" cast into it. These ridges help get the fuel suspended again. A puddle will form but when it tries to flow up and over the ridge it will lose grip on the manifold and be carried off by the air again.

It will depend on what type of driving you do on how quickly it would warm up. In my case I go about 1/8 mile then highway (65 mph) for 9 miles and then there is a stoplight. Still sputtering at that light. Why? Cold air coming into the engine at 3000 RPM at highway speed kept the intake manifold very cold. It would then warm up eventually going thru some more lights in town.

So I bought an Edelbrock 7116 manifold. Checkerboard pattern inside the manifold. Provisions for a heat plenum under the carb/tbi. I plumbed the coolant bypass (big subject for another debate... vortec heads need a coolant bypass) thru this heat plenum. It still sputtered a little bit for the first minute or two but once any heat got into the coolant the intake warmed up a little- and ran fine.

Problem solved... no. Started losing coolant. Not dripping anywhere. Thought it was the good intake manifold gaskets. Replaced those. Same issue. It was still drinking 700 mL every week. I finally pulled the tbi and looked down into the manifold. The waffle pattern had little puddles of coolant. It must have a porous casting and the coolant was leaking thru and being burned off. Edelbrock was NO support at all. Denied it could even happen. Without anything better to try I bought another 7116 (thinking that I had the only defective intake manifold ever made in this universe) and installed that one. SAME ISSUE. At this time I was ready to blow up the whole truck or drive it off a cliff.. fireball... so I dumped in some alumniseal crap (radiator stop leak for aluminum parts) then switched out my 16 lb radiator cap for a 7 lb? 8 lb? and been running like that for 3 years. The first 60-120 seconds it sputters a little bit then after that it is fine.

Is this proper? No. Did I get the only 2 defective 7116 manifolds around? Maybe. They say you can port exhaust thru the heat plenum instead. That might be better... but couldn't figure out a good way to do that.

You must be registered for see images attach

waffle pattern

You must be registered for see images attach

waffle pattern with coolant "sweating" thru the aluminum and forming little puddles

You must be registered for see images attach

the hose under the PCV tubing is the coolant bypass that puts coolant under the carb/tbi

You must be registered for see images attach

the stock GM manifold. No waffle pattern

If I was to go back and try it all over again I'd still keep for vortec heads but would have tried the Edelbrock Pro-flo multi port injection manifold/system. This is pretty much the same as what GM used from the factory. A dry manifold that uses an injector at the last second before the cylinder itself.

Sorry for the book- this issue cost me a lot of time and money. Figured others should laugh (or maybe learn?) at my expense.

I was thinking you are full of **** when I started reading your post. I have a 350/ Vortec heads, the Edelbrock manifold and 1406 carb. It runs great and fires instantly. As I read thru your novel, I admit you make valid points and seem to have done your research.
I'm convinced your on to something. I live in SW Az and our cold days rarely dip into the 40's, so I can't speak from experience.
I'm interested in that heat crossover bypass thing under the plenum. Can you explain more in how the coolant flows? If it comes out if the hose you added, where does it come out?

 

[dcameron787]

I have a k20 and completed the swap last year(lq4) Started out I was just going to use the motor the way it was. Looked very clean, came out of a low mile wreck. Last minute decision was made to open it up to be sure. Well it was toast. Some water got into from sitting out side and needed a rebuild. I ended up putting a cam in, added new 243 heads and headers. I got around 6k in the motor, another 3000k for the swap stuff. Having said that, I am very happy with it. Makes tons of lower and reliable. These are Canadian dollars so around 6-7k US....